Teton County Wyoming

Emergency Management


HAZARDOUS WEATHER


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Phone: (307) 733-9572
Fax: (307) 732-5799

Teton County Emergency Operations Center
3240 S Adams Canyon Dr
Monday through Friday, 8am to 5pm

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Weather

storm clouds coming over the tetons

What is it?

Living in the Rocky Mountain West, weather plays a big role in all of our lives. Even if your profession doesn't have you working outdoors, many of us have to commute long distances over desolate highways to get to work or choose to recreate outside on our days off. When we are prepared, the weather in Wyoming can be handled safely.

 

It is easy to begin taking the weather conditions for granted, and to not prepare for those "what if" events. Something simple like taking a hike in the Tetons in the summer can change in an instant if a rain shower and accompanying cold front move through. Although this situation is hardly a disaster, here in Teton County hypothermia is a risk year round if you don't have adequate clothing (rain gear in the summer, layers of non-cotton clothing in the winter). What was a simple rain shower can become a life-or-death situation if you aren't prepared.

What are the risk factors?

From a disaster standpoint, our main concerns are severe weather events. These would be tornadoes, flood and flash-flood inducing precipitation, severe thunderstorms, severe hail storms, and severe winter weather. I'm sure that many valley residents have experienced at least one, if not most, of these events. Our risk of thunderstorms are higher in the summer, while severe winter weather occurs late and early in the year. An event that may have a few people scratching their heads, however, are tornadoes. There is a myth that tornadoes can't occur in Teton County due to the mountains, elevation, and other factors. Let's dispel those falsehoods right now:

 

  • Tornadoes can't form at high elevations.
    FALSE: The strongest tornado in Wyoming history occurred in Teton County on July 21, 1987 on the Teton Wilderness / Yellowstone National Park boundary near Enos Lake. It was estimated to be an F4 on the Fujita scale (where an F5 is the strongest possible), and was studied by Dr. Fujita himself. Unfortunately, this tornado was not witnessed by anyone since it occurred in the backcountry. Undaunted by this setback, Dr. Fujita used forensic meteorology to determine the strength, area, and direction of this massive tornado. You can read his paper on the subject here (Adobe Reader required).

     

    trees toppled due to teton tornado
    Click for larger image

     

    In the photo above you can see a small portion of the damage caused by this tornado in the form of toppled trees. The trail that you see on the right blocked by trees is the Enos Lake trail. Thankfully no one was injured in this event, but the Forest Service and Park Service estimated damage to forest resources to be in the range of $2.5 million.

    Another high altitude tornado event occurred in Sequoia National Park on July 7, 2004, but this time someone was there to take a photo:

     

    tornado on rockwell pass in sequoia np/ courtesy scott newton
    Click for larger image

     

    The base of the tornado at ground level is estimated to be at least 12,000 feet, making this the highest elevation tornado ever observed in the US. You can read more about this tornado here.

     

  • Tornadoes can't cross canyons/rivers/mountains.
    aug 11, 1999 tornado in salt lake city/ courtesy KTVX news 4 utahFALSE: The Teton / Yellowstone tornado of 1987 ranged in elevation from 8500 feet to 10,000 feet as it went up and down mountains and even crossed the continental divide. An F2 tornado in Salt Lake City on August 11, 1999 descended one side of a canyon and came back up the other side halfway along its path. And the deadliest tornado in US history (Tri-state tornado of March 18, 1925, F5, 695 killed) crossed the Mississippi river without so much as slowing down.

     

  • We just don't get tornadoes out here.
    FALSE: Although the Teton / Yellowstone tornado is the only confirmed tornado to hit Teton County, it was a massive one and only proves that they can happen here. On September 5th, 2007, tornadoes were seen outside of Soda Springs, Idaho. That same storm system produced what is known as a radar-indicated tornado 20 minutes southwest of Hoback Junction. A radar-indicated tornado means that there is a signature on the radar that can be, but isn't always, a tornado. These radar-indicated tornadoes have to be confirmed by weather spotter reports to actually prove that they are a tornado in the field. There weren't any visual confirmations of this radar-indicated tornado, so it isn't classified as an official tornado.

     

    'hook echo' indicating a possible tornado on radarThe fact is we do get tornadoes out here, but due to our low population density, there usually isn't anyone around to see them. If you plot out the tornado reports across the state of Wyoming, interestingly enough a very high percentage of them are seen along Interstate 80 and Interstate 25. This isn't because tornadoes like the interstate, it's because that is where people are to call in the reports of tornadoes.

What should I do?

There are many different types of severe weather events that can occur in Teton County. If you have an all-hazards preparedness plan, you are well on your way to being ready. The next step is to stay informed and learn more about the different severe weather events:

 

 

  • As for any disaster, have a plan and preparedness kit ready for your family.
    If you don't have a family emergency plan and a 72 hour kit, click here to get started.

     

  • Have a NOAA All-Hazards Weather Radio in your home and office.
    NOAA weather radio logoNOAA All-Hazards Weather Radio receivers are a cheap and effective way to stay informed of severe weather events and other disasters. Our local National Weather Service (NWS) office in Riverton,WY, transmits weather conditions and forecasts 24/7 over these radios. This is an extensive network of weather radio repeaters that covers most of the nation. These radios aren't just for weather, though. They can also alert you of chemical spills, avalanche warnings, AMBER (abducted child) alerts, and many other hazardous situations. Teton County Emergency Management will use NOAA All-Hazards Weather Radio to not only alert the public during a disaster, but to also give instructions as to what to do. Many local retailers including hardware, electronics, and grocery stores carry these radio receivers. They range in price from $15 to $70, with full featured models running around $35. Check this link to learn more and listen to what NOAA All-Hazards Weather Radio sounds like.

     

  • Know where to get weather information.
    NOAA All-Hazards Weather Radio is a great source for weather information, but there are others:

     

    • Local radio stations
      Local radio stations 95.3FM, 96.9FM, 1340AM, and 90.3FM broadcast weather information. Only 95.3FM, 1340AM, and 96.9FM, however, will broadcast local Emergency Alert System (EAS) statements. 90.3FM will broadcast statewide EAS statements.

       

    • Our local National Weather Service website
      www.weather.gov/riverton is the place to go for our local National Weather Service forecast. At the top of the page you'll see a clickable map of Wyoming that displays all current weather advisories, watches, and warnings. Once you click on your area of interest, you'll get the local forecast and current conditions.

       

    • Bridger-Teton National Forest's Backcountry Avalanche Center website
      www.jhavalanche.org is the place to check backcountry avalanche hazards and conditions.

       

    • Local weather station information from the MesoWest website
      If you are really into weather, or just want to see the weather differences across the valley, check out this site. It provides you with a clickable map of all weather stations (private, NWS, and otherwise) that report their data to the MesoWest weather network. It defaults to NWS stations, so to see all weather stations use the drop-down menu on the left labeled "Network:" and choose "All Networks".

       

    • wydot logoWyoming Department of Transportation
      This site is maintained in the winter with road conditions, but the webcams across the state highways are up all year round. To check it out, go to wyoroad.info. You can also get this information over your cell phone by dialing 511. If you are outside of Wyoming, dial 888-WYO-ROAD.

       

    • The National Climatic Data Center's Storm Event Database
      This database contains severe weather statistics for events from around 1950 to the present day. Since data must be entered as it is compiled, there is usually a 90-120 day lag on the most current information available. You can search by state, county, date range, event type, and magnitude. This is an interesting way to see what severe weather events have impacted an area in the past. Check it out here.

     

     

  • Learn more about tornadoes.
    NOAA logoCheck these links to learn about tornadoes and what you should do if a tornado strikes:

     

  • NWS Riverton's Tornado Safety Page

     

  • NOAA's National Severe Storms Laboratory Tornado Page

     

  • FEMA's Tornado Information Page

     

  • NWS's Online Tornado FAQ

     

  • Are You Ready For A Tornado?
    Adobe Reader required

 

Learn more about severe thunderstorms and lightning.
NWS logoThunderstorms can strike quickly and have many associated hazards. Check out these links to learn more:

 

NWS Riverton's Thunderstorms Page

 

NOAA's National Severe Storms Laboratory Thunderstorm Page

 

FEMA's Thunderstorms & Lightning Page

 

NOAA's National Severe Storms Laboratory Lightning Page

 

Are You Ready For A Thunderstorm?
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Learn more about severe hail storms.
large hailstone/ courtesy NWSHail is not uncommon in Teton County, and it can cause serious bodily injury and damage to property. Check these links to learn more:

 

NWS Riverton's Hail Safety Page

 

NOAA's National Severe Storms Laboratory Hail Page

 

 

Learn more about severe winter weather.
NWS wind chill chartWinter weather is inevitable here in Teton County. Check these links to learn about winter weather and how to keep yourself safe:

 

NWS Riverton's Winter Weather Safety Page

 

FEMA's Winter Storms and Extreme Cold Page

 

NOAA's National Severe Storms Laboratory Winter Weather Basics Page

 

NWS Riverton's Winter Weather Preparedness Guide
Adobe Reader required

 

NWS, Red Cross, and FEMA's Winter Preparedness Guide
Adobe Reader required

 

Become a National Weather Service Weather Spotter.

 

skywarn logoWeather spotters are vital in getting accurate weather forecasts for Teton County. Our weather is very difficult to predict due to our topography, and reports from spotters on the ground for all types of weather events helps our local NWS office immensely. This information also gets relayed back to Teton County Emergency Management, helping us to better prepare the community and react to severe weather. For more information on the weather spotter program, click here.

What are the impacts?

The impacts can be as varied as the severe weather event itself. They can range from minor travel inconveniences to loss of life. Check the links above to see what the impacts are for each weather event.

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Announcements

Local Organizations!
Do you have a group that would be interested in hearing about preparing for and responding to disasters in Teton County? Emergency Management conducts informative presentations for local organizations.

Email us or call 733-9572 for more information or to set up an appointment.

Ask the County
I just recently moved to the area. What hazards should I be aware of?

There are a list of disasters & hazards here. Briefly, some hazards that affect Teton County (in no particular order) are:  
    Earthquakes Avalanches Wildfire Severe Weather Landslides Flooding Flash-flooding Man-made disasters   If you have any questions about these events, email Emergency Management. See Similar Questions