Severe Weather/Thunderstorm

Did you know that there are 20 million thunderstorms in the U.S. per year?

Thunderstorms are a normal precursor to hazards such as lightning, hail, wind, floods and even tornadoes. They are quite prevalent along the Front Range to the eastern plains during the spring and summer. The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. Lightning can occur anywhere there is a thunderstorm, and can even strike miles away from the storm. Looking at where lightning occurs helps describe where the most prevalent thunderstorm activity is in Colorado. For instance, the greatest number of lightning flashes is not found across the high mountain elevations, but rather where the mountains and plains intersect. Lightning causes an average of 55-60 fatalities and 400 injuries each year. These incidents are most common during summer afternoons and evenings. In addition, wildfire ignition by lightning is of great concern in Colorado. Every year, lightning causes numerous fires across the U.S. According to the National Fire Protection Association, lightning causes an average of about 24,600 fires each year.

Hail can also accompany thunderstorms. Colorado’s damaging hail season is considered to be from mid-April to mid-August. Colorado’s Front Range is located in the heart of “Hail Alley,” which receives the highest frequency of large hail in North America and most of the world, so residents can count on three to four catastrophic (defined as at least $25 million in insured damage) hailstorms every year.

Additionally, familiarizing yourself with the terms below may help with what to expect so you can properly prepare.

Severe Thunderstorm Watch ─ Severe thunderstorms are possible in and near the watch area. Stay informed and be ready to act if a severe thunderstorm warning is issued.

Severe Thunderstorm Warning ─ Severe weather has been reported by spotters or indicated by radar. Warnings indicate imminent danger to life and property.

30/30 Lightning Rule ─ You can tell how close you are to a lightning strike by counting the seconds between seeing the flash and hearing the thunder. For every five seconds you count, the lightning is one mile away. If you see a flash and instantly hear the thunder, the lightning strike is very close.

Despite the risk, everyone can take steps in preparing for severe weather. Explore the information below to learn more about severe weather safety precautions!

Cover photo courtesy of Douglas County

Banner photo courtesy of NOAA

Within text photo courtesy of the Fort Collins Office of Emergency Management

Before

  • Build an emergency kit and make a family communications plan.
  • Identify a safe shelter location – a basement is best, followed by interior rooms on the lowest level of the building away from windows. Mobile homes are often unsafe in a tornado – identify a neighbor’s house or public shelter where you can go if a tornado warning is issued.
  • Secure outdoor objects that could blow away or cause damage during a storm.
  • Unplug any electronic equipment before the storm arrives.
  • Obtain a NOAA Weather Radio to receive alerts about impending severe weather.
  • Sign up for reverse telephone alerts for your county, and don’t forget to include your cell phone.
  • Make sure you have sufficient insurance coverage – including flood insurance, which is separate from your homeowners or renters policy.
  • Photograph or take video footage of the contents in your home in case you need to file a claim after a disaster.
  • Store copies of your important documents in another location, such as a bank safe deposit box.

During

  • Avoid contact with corded phones and devices.  Cordless and wireless phones not connected to wall outlets are alright to use.
  • Avoid contact with electrical equipment or cords. Unplug appliances and other electrical items such as computers and turn off air conditioners. Power surges from lightning can cause serious damage.
  • Avoid contact with plumbing. Do not wash your hands, take a shower, wash dishes, or do laundry. Plumbing and bathroom fixtures can conduct electricity.
  • Stay away from windows and doors, and stay off porches.
  • Do not lie on concrete floors and do not lean against concrete walls.
  • Avoid hilltops, open fields, the beach or a boat on the water.
  • Take shelter in a sturdy building. Avoid isolated sheds or other small structures in open areas.
  • If you are driving, try to safely exit the roadway and park the vehicle. Stay in the vehicle and turn on the emergency flashers until the heavy rain ends. Avoid touching metal or other surfaces that conduct electricity in and outside the vehicle.

After

  • Avoid downed power lines and leaking gas lines – report them to your utility company.
  • Watch out for overhead hazards such as broken tree limbs, wires and other debris. Be cautious walking around.
  • Notify your family that you are safe – phone lines may be down, so be prepared to send text messages.
  • Make sure gutters and drains are clear for future rain/flood events.
  • Check the property for damage and if there is damage, take photographs/videos of the damage as soon as possible.  Contact your insurance company to file a claim.
  • Watch your animals closely.

More Information:

References, Resources and More Information:

  • Ready.gov – Thunderstorms and Lightning
  • NOAA Watch
  • Rocky Mountain Insurance Information Association
  • Thunderstorms, Tornadoes, Lightning…Nature’s Most Violent Storms
  • National Weather Service
  • NOAA – Facts about Lightning
  • NOAA – Lightning Safety
  • National Fire Protection Association – Lightning Fires and Lightning Strikes

It Happened Here

On the night of July 20th, 2009, a powerful storm hit the northwest suburbs of Denver, dumping an inch of rain in less than an hour and dropping hail one-inch in diameter. Winds of 80 miles per hour uprooted mature trees; the storm damaged numerous cars, windows and roofs. The storm also left 50,000 residents without power. The Rocky Mountain Insurance Information Association (RMIIA) lists the July 20th storm as one of the costliest hazard events since 1990 in terms of insured losses in the Rocky Mountain Region. RMIIA has identified $767.6 million in damages from the storm.

Fast Facts:

  • Lightning often strikes outside of heavy rain and may occur as far as 10 miles away from any rainfall.
  • Of the estimated 100,000 thunderstorms that occur each year in the U.S., about 10 percent are classified as severe.
  • A study in the Denver area found that 1 out of every 52 lightning flash results in an insurance claim.
  • The chance of being struck by lightning in the U.S. in a given year is 1 in 500,000.
  • Colorado averages 529,000 lightning flashes per year.
  • Flash floods are the number one thunderstorm killer; lightning is second.
  • The energy from one lightning flash could light a 100-watt light bulb for more than 3 months.
  • How close is the lightning?  Find out about the 30/30 lighting rule below!