A1]
Geographic Location
Sitting in between the Olympic Mountains to the west and the Cascade Mountains to the east,
Seattle: Latitude: 47.63 N, Longitude: 122.33 W
The Puget Sound is the lifesource for most of the population in
Mt. Rainer - the tallest peak in the Cascade Mountains to the east of Seattle.
What effects does Mt. Rainer have on the Pacific northwest? If and when Mount Rainer erupts, it can have devastating impacts. Many predict the eruption will be similar to that of Mount St. Helens, producing pyroclastic flows that destroyed everything in its path for 4 miles from the summit and nearly incapacitated other wildlife for the next 9 miles, when Mt. St. Helens erupted. Unlike Mt. St. Helens, Mt. Rainer sits much closer to many more populated areas. Other non-volcanic events have already proven to be destructive in the past. Most of these are lahars and avalanches falling from the very steep slopes of the volcano due to earthquakes, which happen about 30 times every year. One debris flow went 60 miles, until it was halted by the Puget Sound! [A35] These lahars and lava flow won't only affect the land nearby the mountain, but can affect vegetation, the quality of water, and cause inestimable amount of monetary damage. [A36] The last time Rainer erupted was 2,200 years ago, but is the third most active volcano in the Cascades.
Distances from
Topography
When founded, Seattle was built upon the Seven Hills of Seattle. Although much of the downtown area has been leveled off by human development, the city is still noticeably hilly, with an elevation range of 0-450 ft. above sea level. A15
In addition to re-grading projects that have leveled the city off, many man-made bodies of water exist within Seattle including the Duwamish Waterway and the Lake Washington Ship Canal. The latter connects Lake Washington and the Puget Sound across the city, allowing eastern Washington access to the Pacific Ocean. A total 41% of Seattle is covered by water. A10
Features that define Seattle A15, A10, A16
Puget Sound- Located to the west of Seattle it covers 1,020 square miles, has an average depth of 450 ft., and a maximum depth of 930 ft. just north of Seattle. The Sound allows Seattle access to the Pacific Ocean.
Lake Washington- Located to the east of Seattle, it is the second largest natural lake in the state of Washington. It covers 54.4 square miles, has an average depth of 108 ft., and a maximum depth of 214 ft.
Olympic Mountains- West of the Puget Sound, the Olympic Mountains can be found. The mountains are not exceptionally tall and have a maximum height of 7,962 ft.
Cascade Mountains- Located East of Lake Washington, the Cascade Mountain range spans 700 miles and has a maximum height of 14,410 ft.
Seattle is surrounded by bodies of water. A9 Mountain Ranges also surround Seattle. A11
Population
According to the 2006 U.S. census the population of Seattle, Washington is at 562,106 residents. Gender is almost split down the middle with 49.6% of the residents being female while the other 50.4% are male. Whites make up the majority of the population at 70% followed by Asians at 13.0% followed by African Americans at 8.2% with the rest of the population being split between various other races. There is an estimated 282,414 households with 91.8% of those households being occupied. An estimated 346,584 residents over the age of 16 are employed making a median salary of $58,311 which is a little less than $10,000 more than the U.S. median. A12
Climate
Seattle has a temperate climate and is known for its rainy weather. However, the rain in Seattle is usually light or misty, unlike what we as midwesterners think of as rain. The normal average annual precipitation total for Seattle is 37.07 inches. The rainy season in Seattle doesn't officially begin until Ocotber 1. This leads into winter, which is the wettest season. Surprisingly, Seattle only has a mean annual snowfall of 7.1 inches -- it snows in the surrounding mountains. Spring in Seattle is mild and green, but like anywhere, can be very wet at times. Summers in Seattle are usually warm, dry, and sunny, with long days (because of its latitude) and cool nights. The driest time of the year in Seattle is the last half of July and the first half of August. The warm, mild weather often continues into fall, with cooler temperatures at night. A13, A14
By Road
Seattle has a very good bus system that travels all throughout the city and surrounding areas. It is serviced by Greyhound and Gray Line of Seattle within the city. A22
Interstate 5 – Goes north/south through the city of Seattle thereby connecting it to suburbs to the north and south of the city. Interstate 5 connects many of the major west coast cities to Seattle including; Los Angeles, Portland, Sacramento, San Diego, San Francisco, and Vancouver, Canada. A23
State Route 99/Alaskan Way Viaduct – Also goes north/south through the city of Seattle, however the state route is limited to the state of Washington so while it connects Seattle to its suburbs. State route 99 is a local highway so it doesn't connect it to other major cities on the west coast. The Alaskan Way Viaduct is a section of SR99 that is elevated and overlooks Elliott Bay. This makes the Alaskan Way Viaduct one of the more scenic routes of Seattle. There have been recent concerns that the Alaskan Way Viaduct may not be able to stand up to an earthquake and there is a legitimate chance that it will be shut down. Because of this there are several plans on ways to rebuild or replace the viaduct. A24
Interstate 90 – Goes east/west all the way across the country from Seattle to Boston and goes through cities like Chicago and Cleveland. Interstate 90 is the longest interstate in the country. A25
Road Map of the greater Seattle Area. A41
By Rail
King Street Station – King Street Station is the major train station in Seattle, which is serviced by Amtrak’s 12 Washington State trains and two Amtrak long distance trains. (Those being the Coast Starlight and the Empire Builder). A24
King Street Station A42
By Air
Seattle-Tacoma International Airport - Although there are some smaller airports in and around Seattle the primary passenger airport is the Seattle-Tacoma International Airport in SeaTac, Washington. Over 31 million travelers went through SeaTac airport in 2007. A26
By Sea
Seattle has the largest ferry system in the United States which services eight counties and 10 different routes in Washington. A24
Economics (Alake Kashyap)
Seattle has a history of boom and bust cycles, which usually happens with cities that are as large as Seattle [A17]. Seattle has risen as a company town (A company town is a town or city in which most or all real estate, buildings, utilities, hospitals, small businesses such as grocery stores and gas stations, and other necessities or luxuries of life within its borders are owned by a single company), then gone into abrupt decline, but it has typically used those periods to successfully rebuild infrastructure A17.
In 2006, Expansion Magazine ranked Seattle among the top 10 metropolitan areas in the nation for climates favorable to business expansion and one of the top 20 cities to live in [A18]. In fact, five companies on the 2006 Fortune 500 companies have headquarters in Seattle [A19] Among those are Washington Mutual, Amazon.com, Nordstrom, Starbucks, and Safeco. Boeing used to be the largest company in Seattle, but relocated its headquarters to Chicago.
During World War II, Seattle was the major point of departure for troops leaving for the North Pacific, and Boeing manufactured a lot of the war's bombers (aircrafts). The local economy fell after the war, but climbed after a period with the expansion of Boeing. The climb ws due to the growth of the commercial aviation industry. When this cycle went into a downturn in the late 1960s and early 1970s, many people left the area to look for work somewhere else in the US. It got to a point where local real estate agents put up a billboard that read "Will the last person leaving Seattle – Turn out the lights." [A20]
Technology companies, including Microsoft, Amazon.com, Real Networks, McCaw Cellular, T-Mobile USA, and biomedical corporations such as HeartStream, Heart Technologies, Physio-Control, Medtronic, ICOS, and Immunex, are located in Seattle.. This success produced an increase of new citizens with a population increase within city limits of close to 50,000 between the 1990 and 2000 Census. Seattle's real estate become some of the most expensive in the country. In 2005, Forbes ranked Seattle as the most expensive American city for buying a house based on the local income levels. A21
Ecology
Coniferous Forest Harbour Seal Black-Tailed Deer The Puget Sound
Before it was cultivated and settled, the Seattle area was characterized by dense coniferous forests most commonly made up of western red cedar, western hemlock, and Douglas-fir. Animal species native to this area include raccoon, sea otter, mink, coyote, black-tailed deer, and the harbour seal. Some birds native to the are are the turkey vulture, bald eagle, blue grouse, seabirds, shorebirds, and waterfowl.
Currently, only about 5% of the original habitat remains due to heavy population growth and urbanization in the area. The ecoregion has therefore been given a conservation status of critical or endangered.A28
Washington's soil is known as Tokul soil. This soil is found west of the Cascade Mountains in the Puget Trough. They extend from south of Seattle up to Canada. Tokul soils, made from volcanic ash, support the coniferous forests present in Washington.A29
Washington is also undertaking a project to restore Seattle's main source of water, The Puget Sound. Along with help of several local governments steps are being taken to improve the aquatic ecosystem of The Puget Sound. Oxygen levels in the water have become so low from chemical pollution that marine life such as fish, crab, sea stars, wolfeels, and octpi are suffocating. In May 2007 The Puget Sound Partnership was formed. This organization was created by the Governor of Washigton in order to create an agenda for actions to save the delicate ecosystem.A32
Land Usage and Other Information
Surrounded by mountains and water, the greater Seattle area features picture-perfect views and abundant recreational opportunities year-round. The city is 84 squares miles in size and has around 6,900 people per square mile. The population of the urban city of Seattle is 569,101 while the entire metropolitan area has a population around 3 million. The metropolitan area also includes cities like Tacoma, Bellevue, and Everett. Seattle is a member of King County, Washington which covers 2,126 square miles of land and also 180.5 square miles of water.A30 Seattle is home to 430 parks which occupies approxametly 6,200 acres or 11% of the cities land area. The largest park in the area is Discovery park which spans 534 acres. The oldest park in the city is Denny Park which was first opened in 1884. A43 Seattle, Washingson is also home to a 3 1/2 acre Japanese Garden National Park. The park features several tea events over the summer. A44 A vast majority of Seattle's land use does not actually occur on land but on the water. One of major commodity exports in the area are fish.A31
[A28]
Bibliography:
A1 - http://www.hoteldeca.com/assets/03A5EA32-693D-4D73-9F45-2999873FF6AB.jpg
A2 – http://www.city-data.com/city/Seattle-Washington.html
A3 – http://www.gonorthwest.com/Washington/puget/Puget_Sound.htm
A5 – http://www.timeanddate.com/worldclock/distances.html?n=234
A6 – http://pics2.city-data.com/city/maps2/cm22.png
A7 – http://vmedia.rivals.com/uploads/992/101922.gif
A8 - http://www.flatrock.org.nz/topics/environment/assets/mt_rainer_clouds.jpg
A9- http://en.wikipedia.org/wiki/Image:Seattle_07752.JPG (Image taken by a Wikipedia user)
A10- http://www.exhibits.pacsci.org/puget_sound/PSGeology.html
A11- http://cses.washington.edu/cig/figures/web_pnwtopo1_BIG.jpg
A12- http://factfinder.census.gov/servlet/ACSSAFFFacts?_event=Search&geo_id=&_geoContext=&_street=&_county=seattle&_cityTown=seattle&_state=&_zip=&_lang=en&_sse=on&pctxt=fph&pgsl=010">http://factfinder.census.gov/servlet/ACSSAFFFacts?_event=Search&geo_id=&_geoContext=&_street=&_county=seattle&_cityTown=seattle&_state=&_zip=&_lang=en&_sse=on&pctxt=fph&pgsl=010
A13 – http://www.beautifulseattle.com/clisea.htm
A14 – http://www.cdc.noaa.gov/cgi-bin/USclimate/city.pl?state=WA&lane=fast&itypea=1&loc.x=217&loc.y=145&.cgifields=itypea
A15- http://www.seattle.gov/transportation/steepest.htm
A16- http://dnr.metrokc.gov/wlr/Waterres/lakes/biolake.htm
A17- http://www.villagelife.org/news/archives/5-20-97_rebuildingSeattle.html
A18- http://www.butlercounty.biz/PDF_files/Press_Releases/2006_Americas_Hottest_City.pdf
A19- http://www.visitseattle.org/media/pkHistory.asp
A20- http://www.historylink.org/essays/output.cfm?file_id=1287
A21- http://seattletimes.nwsource.com/html/realestate/2002446059_homeprices21.html?syndication=rss&source=realestate.xml&items=7
A23- http://www.fhwa.dot.gov/reports/routefinder/table1.cfm
A25- http://www.interstate-guide.com
A26- http://www.portseattle.org/seatac/
A27- http://www.pacificnaturetours.com/images/ForestLight.jpg
A28- http://www.city-data.com/city/Seattle-Washington.html http://www.nationalgeographic.com/wildworld/terrestrial.html?id=1&mapServiceName=WW_Terrecos&locWidth=120&locHeight=72&cMinx=-122.436232&cMiny=47.495375&cMaxx=-122.224659&cMaxy=47.734561&size=undefined&detail=undefined
A29- http://soils.usda.gov/gallery/state_soils/#list
A29 - http://www.cityofseattle.net/oir/datasheet/location.htm
A30- http://www.city-data.com/county/King_County-WA.html
A31- http://www.fishing.about.com/b/2006/02/09/seattle-area-fishing-report.htm
A32- http://www.ecy.wa.gov/puget_sound/Overview.html
A35 - http://volcano.und.edu/vwdocs/volc_images/img_rainier.html
A36 - http://www.emporia.edu/earthsci/student/zellers1/rainier.htm
A37 - http://www.3dsquared.com/imagesl/pan/MarcA/Summer-Dawn.jpg
A38 - http://images.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/7/73/Harbour_seal.jpg/800px-Harbour_seal.jpg&imgrefurl=http://commons.wikimedia.org/wiki/Image:Harbour_seal.jpg&h=529&w=800&sz=70&hl=en&start=1&sig2=szgU1JlY5GHXb-FeVv4nIQ&um=1&tbnid=GaeODe8iaK0RJM:&tbnh=95&tbnw=143&ei=wJ_9R6zKAqjmigHjypGEAQ&prev=/images%3Fq%3Dharbour%2Bseal%2Bimages%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official
A39 - http://cache.eb.com/eb/image?id=65530&rendTypeId=4
A40 - http://www.acm.vt.edu/~jchen/photoAlbum/Seattle/Space%20Needle%20-%20Puget%20Sound.jpg
A41 - http://www.aaccessmaps.com/show/map/seattle_overview
A42 - www.city-data.com/
A43- http://www.seattle.gov/parks/quickfacts.htm#parks
A44- www.seattle.gov/parks/parkspaces/japanesegarden.htm
http://www.komotv.com/news/10686711.html" class="WikiLink">A45 - http://www.komotv.com/news/10686711.html
http://www.blueprintforsafety.org/hail/hformation.aspx#top" class="WikiLink">A46 - http://www.blueprintforsafety.org/hail/hformation.aspx#top
Lightning
By Steve Nowicki
Lightning over the Puget Sound [B1]
Frequency
Thunderstorms occur frequently north and south of Seattle due to the Puget Sound Convergence Zone, but the city of Seattle sees only the occasional summer thunderstorm. Because of this lightning is a rarity for the city itself, but it can be seen in the distance in the convergence zone as shown above throughout the summer months. [B10]
Formation
There are many hypothesis regarding the formation of lightning, however the most prominent include Interface and Induction Charging.
Interface Charging
Interface charging deals with ice formations that exist within a thunderstorm cloud, and there are two types that are involved; small ice crystals and hailstones. Since these two formations are formed by different processes and are different sizes, they have different electrical charges. This difference in charge creates an electrical field between the two formations such that when the two collide, electrons will be transferred from the small ice crystal to the hailstone. Following this transfer, the small ice crystal will be left with a positive charge and will be swept up to the top of the cloud by the storms updraft and the heavier hailstone will continue to fall with a negative charge. This leaves the thunderstorm cloud with a positive top and a negative bottom. This difference in charge between cloud regions is what generates lightning. [B8]
Induction Charging
Induction Charging is a feedback mechanism that reinforces and accelerates interface charging. As interface charging creates an electrical field within the cloud, protons within each ice particle will migrate to the top of the particle and electrons will migrate towards the bottom. This arrangement enhances interface charging. [B8]
When Lightning Strikes
Lightning occurs because regions of the thunderstorm cloud become extremely positive or negative and contain a lot of energy. These regions either have protons or electons that are attracted to their opposite charge, and when they find them a lot of energy is transferred, creating the lightning bolt. Lightning can occur within a cloud itself, from cloud to cloud, or from cloud to ground. When lightning strikes the ground, protons or electrons are connecting with positive or negative regions of the ground.
Lightning formation [B9] Interface Charging enhanced by Induction
Lasting Impacts
The amount of energy within in a lightning bolt is simply enormous. The current within the bolt contains between 15,000 and 30,000 amperes and bolt temperatures are five times greater than the surface of the sun. Obviously whatever lightning strikes it will destroy. Seattle only occasionally experiences lightning, but its deadliness is for the most part prevented by lightning rods on the city's skyscrapers. [B8]
What lightning can do [B11]
Drought Case Study Mark Baker - mpbaker2
A drought is an extended period of time of persistently dry weather that can cause serious economic concerns such as crop damage and shortages in water supply. Size, moisture deficiency, and duration are all factors considered into the severity of a drought. [B2]
Droughts are the most deadly natural disaster worldwide. Droughts are different in all different regions. What may be typical weather conditions in one area may be disastrous conditions elsewhere. There are actually four different types of droughts: meteorological, agricultural, hydrological, and socioeconomic.
Meteorological drought – A measure of the break off of normal precipitation levels for a certain area.
Agricultural drought – When the amount of moisture in the ground is no longer sufficient for a certain type of crop to exist.
Hydrological drought – When surface and subsurface water supplies are below normal.
Socioeconomic drought – A situation that occurs when a decrease in water supply begins to affect people’s lives. [B2]
[B6]
The picture above shows the current drought index for Seattle, WA. As you can see, there is no sign of a drought through the entire state.
Case: Seattle Drought of 2001
In 2001,
The chart below shows the cumulative rainfall for
[B7]
The drought of 2001 brought many problems among the people of
By the end of 2001 there had been 57 emergency water right permits and changes of existing water rights. 75,000 acres of land used for farming had been shut out of commission, 25,000 acres of orchards had been pulled out, and the entire sugar beet industry was out of production. [B4]
On September 5th, 2001,
[B12]
THUNDERSTORMS bemoras2
FREQUENCY- While rain is very prevalant in Seattle, thunderstorms are rather uncommon. The National Oceanaic and Atmospheric Administration only has a record of 8 reported cases thunderstorms and high winds since 1950 in the King County area.[B13] While Seattle experiences very rare cases of thunderstorms, they are very prevalant in the areas north and south of Seattle due to the Puget Sound Conversion Zone. [B10]
[B14]
FORMATION- All types of sever thunderstorms require the same four basic elements in order to form. 1) A source of moisture 2) a condtionally unstable atmosphere 3) a mechanism to trigger the thunderstorm's updraft (this can occur either through lifting or heating of the surface) 4) vertical wind shear. There are however, expections to these elements. For example, an airmass thunderstorm can form in the absence of a vertical wind shear. this thunderstorms are also known as isolated thunderstorms and tend to last for only a few hours. There are also Mesoscale Convection Systems. These storms are known for this damaging straight-line winds and heavy rainfall. Frontall Squall Line storms are the largest of all thunderstorms with the squall line stretching hundrerds of kilometers long. Finally, there are supercells. These are by far the most damaging and severe type of thunderstorm there is. The unique thing the storms is that due to its circulation, it behaves as one large storm rather than smaller storm cells. [B8]
[B15] [B16]
LASTING EFFECTS- The are numerous lasting effects of thunderstorms due to what accomapny thunderstorms. Most thunderstorms are accompanied with lightinging with has enough electrical engery to burn 5 times hotter than the surface of the sun. High winds also frequent thunderstorms. Winds gusting to high speeds can knock over trips, toss debry and damage homes. It is also a possibilty for tornados or microbursts to develop out of thunderstorms. High property damage and human casualties can occur from what develop out of thunderstorms. The largest amount of damage recorded by a thunderstorm on Seattle adds up to $25,000.[B13]
TORNADOES
Amanda Lerner (alerner2)
[B22]
A tornado is defined as a violently rotating column of air extending from a thunderstorm to the ground. They often develop out of severe thunderstorms. Below is a description of the stages of formation of a tornado. [B18]
Before thunderstorms develop, a change in wind direction and an increase in wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere. |
Rising air within the thunderstorm updraft tilts the rotating air from horizontal to vertical. |
An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation. |
A lower cloud base in the center of the photograph identifies an area of rotation known as a rotating wall cloud. This area is often nearly rain-free. Note rain in the background. |
Moments later a strong tornado develops in this area. Softball-size hail and damaging "straight-line" winds also occurred with this storm. [B18] |
The Puget Sound Convergence Zone, an area where wind blown in from the ocean and split by the Olympic Mountain range converges, also contributes to the formation of tornadoes in the Seattle area. [B20] Some tornadoes can also develop out of waterspouts. A waterspout is a weak tornado that develops over water and can sometimes move inland and become tornado. [B18]
Although the probability of tornadoes striking Seattle are very weak, it is not impossible. The National Weather Service believes that tornadoes are actually under-reported in the Northwest, due in part to a common belief that tornadoes do not occur in this region. In recent years, with a growing population, more reports have been made. Below is a chart of major tornado incidents reported in Seattle and the surrounding areas.
Currently, Seattle does not have an audible warning system to alert inhabitants of tornadoes, except along the waterfront. [B17] Western Washington experiences only a few tornadoes each year. Tornadoes are associated with a few changes that can act as warning signs, though, such as dark, greenish skies, large hail, a wall cloud, a loud roar, and heavy storms. [B18] The last major tornado in Western Washington touched down in Vancouver on April 5th, 1972, and killed six people. [B19]
Major Incidents [B17]
Year |
Location |
Size |
Impacts |
1997 |
King County |
F0 |
Four F0 tornadoes confirmed in western King County. None caused damage. |
1972 |
Vancouver, WA |
F2 |
This region storm demonstrates that deadly tornadoes have happened in the Northwest. An F2 tornado developed as part of a regional windstorm near Portland, Oregon. It moved across the Columbia River and killed six people, injured 300 more and caused $6 million in damage in Vancouver, Washington on April 5, 1972. |
1969 |
Seattle |
F3 |
A tornado (F3) in South King County topples signs and damages buildings causing $500,000 in damage. This tornado occurred during a regional windstorm. It started as a waterspout then moved inland. |
1962 |
Seattle |
F1 |
The area's first confirmed tornado (F1) touches down west of Sand Point, severely damaging several homes. It picked up a carport and tossed it down onto the neighboring house. Everyone in the house was caught by surprise, but there were no casualties. |
Case Study:
First Recorded Tornado in Seattle
September 28, 1962
[B18]
On September 28, 1962 at approximately 5:55 p.m. a witness saw two clouds merge into a funnel and reach the ground, bringing with it 100 m.p.h. winds. Nicknamed "Bouncing Betty" by the locals, the tornado first hit near the Sand point area of Seattle, and in 15 minutes traveled across Lake Washington to Juanita. The tornado damaged eight homes in Sand Point, formed a 100 foot high waterspout over Lake Washington, and finally toppled 70 trees when it hit Juanita. Many fences, roofs, and cars were damaged by debris but no fatal injuries were recorded. After about 15 minutes, the funnel cloud spun back into a mass of gray clouds that was otherwise a typical late summer storm.
Strong thunderstorms are common in the Seattle area, but the tornadoes that can sometimes develop are not. Given that so many bodies of water surround Seattle, it is a common misconception that tornados cannot affect the area. The tornado of 1962 illustrates this point because it was not well forecasted. Many residents, instead of taking precautionary safety steps, watched in amazement as the tornado passed through their towns. Although there were no fatal injuries, there were some damages to personal property. [B21]
If nothing else, the 1962 tornado acted as a warning to residents of the area. Although tornadoes are uncommon in the Seattle area, they are not impossible. This was the first recorded tornado in Seattle's history but it was not the last.
Mountain Snowstorms
[B26] "Avalanche in Motion"
Frequency
Since 1993, there have been four major floods in the Seattle area. The biggest being in Snoqualmie Falls. A Pacific weather system brought large amounts of rainfall from November 2 through 7. This caused flooding until November 11th. This storm caused 104 homes to be destroyed, 206 homes with major damage, and 572 received minor damage. In total, this storm costed 11.1 million dollars in property damage. That accounts for 45.3% of the total cost of all floods in Seattle since 1993 [B27].
Below is a clip of Snoeualmie Falls during its flooding stage.
[B28] pictured above, flood damage to a town South of Seattle [B32, B33]
Time of the year floods occur
Floods in the Seattle area tend to occur later in the year, contrary what many people think (that flooding usually occurs in the Spring). Looking at the data over the past 15 years, 75% of the floods that have taken place in the Seattle area have been in September or later. In fact, the most damaging flood (Snoeualmie Falls) took place in November, as mentioned above [B27]
How floods develop meteorlogically
How floods develop meteorologically is fairly simple. It usually takes a thunderstorm to produce floods, but it can also be caused by non-stop continuous rain over an extended period of time. Rain plays a role in the hydrologic cycle in which moisture from the oceans evaporates, condenses into drops, precipitates (falls) from the sky, and eventually returns to the ocean via rivers and streams to repeat the cycle again. However if the rain continues to fall over an extended period of time, or very rapidly over a short period of time, floods have a very good chance of taking place [B32]
Lasting Impacts
Below I have posted two examples of what type of damage and lasting impacts floods can do to the Seattle area. the videos below are from storms that have caused major flooding in the metropolitan Seattle area.
[B29, B30]
Unique Aspects
There are a few unique aspect to floods and the Seattle area. First, I found it quite surprising that the amount of floods that occured were not much higher. Seattle has a reputation for being a city where it rains constantly. To have found only 4 major floods in the past 15 years really caught me off guard. I did notice that since 1993, there have been 227 recorded floods in all of Washington [B27]. The most expensive flood occured in Lewis County, totaling 50 million dollars, or 20% of all costs of the 227 recorded floods combined.
Below, a few images of what floods have done as far as damage goes in the Seattle area [B32, B33]
[45]
Brian Bajjalieh (bbajjal2)
Frequency
Hail is a common occurrence in severe thunderstorms however severe thunderstorms are not a common occurrence in
Formation
Hail is formed when there are up drafts of warm air and down drafts of cold air present in severe thunderstorms. If the downdraft temperature is below 32ºF, raindrops will freeze [B35]. The frozen raindrops can repeat this cycle many times and with each time the drop will warm and refreeze getting larger and larger with each pass and once the now hailstone is heavier than the force of the updraft it will fall to the ground [B35].
Aspects and Impacts
Hail is not very unique nor does it have lasting impacts to
Wind Storms
by: cwendt
The strongest wind events in Puget Sound and the Seattle area typically occur in the fall and wintertime when many storms tend to make landfall across the southern tip of Vancouver Island or the northern tip of Washington State. As the storms track inland, it creates a direct wind path to the low-lying Puget Sound area. The winds are enhanced by the topography here, the Olympic Mountains to the west and the Cascade Mountains to the east, or the I-5 corridor (named as such for Interstate 5 that runs north-south through the area). The storm creates a low pressure to the north, and the higher pressure air to the south races up the corridor and is essentially "squeezed" by the mountains on both sides, accelerating the air as it moves up the corridor.
Seattle is right in the middle of this corridor and receives strong winds anytime a storm comes inland in this way. The speed of the winds depends on the strength of the storm, the track, how strong the pressure gradient, etc. Winds can also be blown over the Cascade Mountains creating strong gusts in the Puget Sound area.
These winds can topple trees, downing phone and power lines and wreaking havoc on cars, homes, and businesses. These create long delays and detours and can cause major monetary damage. [B36, B37, B38]
Case Study - Hanukkah Eve Wind Storm of 2006 - Scott Manson - manson2
The Hanukkah Eve Wind Storm occured on December 14th of 2006 and dissipated on the 15th. It was a Pacific storm that hit the northwest coast of the United States, directly impacting Seattle and the surrounding area. The storm was extremely damaging not only from winds but also the heavy rain associated with the storm. This led to much flooding in the lower laying areas around Seattle. Thousands of trees were uprooted which caused damage to houses, power lines (which resulted in the loss of power to over one million people.) There were a total of 15 fatalities in the Seattle area, only four of which were as a direct result of the wind storm. The others died later due to complications that arose out of the wind storm. This windstorm formed on the 13th of December, giving only a day to forcast the event before it hit into the West Coast of the United States. The storm was fairly typical although windstorms in the Western part of the country are typically east of the Rocky Mountains and are Chinook type windstorms. This windstorm was typical in terms of the type of effects and windspeeds. Wind gusts reached over 100 miles per hour with also very high sustained wind speeds. The amount of rainfall was perhaps atypical because while associated with windstorms, the amount of rain in some areas during this windstorm set unprecedented records. The implications for Seattle and the surrounding area were devastating. As mentioned previously there were numerous fatalities along with over 250 hospitalizations for other injuries. Between Washington and Oregon there were 220 million dollars of insured damages to structures. Due to this storm Seattle and the surrounding area examined how to better prepare for an event of this nature in the future. [B42] [B43]
[B41]
Heat Waves - Scott Manson - manson2
Overview
Heat waves are periods of unusually hot weather for a given period of time. The reason this definition is vague is because heat waves are defined differently depending on certain areas of the
The National Weather Service will issue a heat advisory in the
Frequency of Heat Waves in
Development of Heat Waves
There are many factors that contribute to the development of a heat wave. The first perhaps being the most obvious is the absence of polar air masses that can move into the region. Typically
Unique Aspects of Heat Waves in
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[B12]- http://z.about.com/d/saltfishing/1/0/X/1/clouds2.jpg
[B13]- http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dll?wwevent~storms
[B14]- http://earthstorm.mesonet.org/materials/graphics/TstormFreq.gif
[B15]-http://images.google.com/imgres?imgurl=http://www.ux1.eiu.edu/~jpstimac/1400/FIG10_003.JPG&imgrefurl=http://www.ux1.eiu.edu/~jpstimac/1400/tstorms.html&h=600&w=800&sz=122&hl=en&start=10&um=1&tbnid=hG43S7MqSNpJ1M:&tbnh=107&tbnw=143&prev=/images%3Fq%3Dthunderstorm%2Bformation%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DN
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[B29] - http://www.youtube.com/watch?v=HTxmnf3o_Bs
[B30] - http://www.youtube.com/watch?v=tP-THaSNufo
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