DENVER — It’s that time of year again. Severe weather season is upon us, and damaging hailstorms are one of the biggest concerns in Colorado this time of year.
Damaging hail is anything larger than a quarter in size, and it can be produced by any severe storm. But the dimensions can range all the way up to the diameter of a fully-grown grapefruit.
Here are seven things you need to know about hailstorms in Colorado:
1. How much hail do we get?
In a typical season, which is from mid-April to mid-August, the Front Range sees about three or four catastrophic hailstorms, according to the Rocky Mountain Insurance Information Association.
Colorado, along with Nebraska and Wyoming, makes up what meteorologists call “hail alley.” The area averages seven to nine hail days per year.
According to the National Severe Storms Laboratory, the reason why this area gets so much hail is that the freezing levels (the area of the atmosphere at 32 degrees or less) in the high plains are much closer to the ground than they are at sea level, where hail has plenty of time to melt before reaching the ground.
2. How large can hail get?
Hail is usually pea-sized to marble-sized, but big thunderstorms can produce big hail. Baseball-sized hail pounded parts of Golden and Lakewood during last year’s record-breaking storm.
The largest hailstone recovered in the U.S. fell in Vivian, SD on June 23, 2010, with a diameter of 8 inches and a circumference of 18.62 inches. It weighed 1 lb 15 oz, according to the NSSL.
3. When to take cover
Ideally, when a thunderstorm approaches, most people run for cover to be indoors, as lightning strikes can also be fatal. Any storm that produces severe thunder and lightning has the potential to produce hail.
If you're still outside when hail falls, seek immediate shelter.
Those who are in cars should pull up next to a building, under a gas station's overhang or pull into a garage and attempt to wait out the storm. When waiting out the storm, consider wrapping up in a blanket to shield from a potential shattered windshield.
Hail over a quarter in diameter — depending on wind speeds — can kill humans, pets or livestock if it strikes in the correct location.
4. Prepare in an abundance of caution for large, damaging hail
If possible, avoid the area in which hail will fall with the help of the forecast. If not, try to store your vehicle under a carport or in a garage.
When you have no shelter for your car, place a cardboard box on your windows and windshield. When winds are at normal speeds and hail is smaller than a ping pong ball, card board boxes can prevent windshields from cracking.
5. Take caution while driving not to put others in danger
When driving into a hailstorm you didn't realize would happen, don't park under an overpass. Parking under an overpass is severely dangerous due to a phenomenon known as hail fog, which arises when the cold hail hits hot ground. Hail fog can be worsened by exhaust from cars.
When a number of cars park under an overpass, it can be nearly impossible for other drivers to see what may be ahead. This has caused a number of tragic accidents.
6. Costly damage
According to the Rocky Mountain Insurance Information Association, Colorado had the second highest number of hail claims in the US from 2013-2015 (182,591), second only to Texas.
According to RMIIA, the costliest hail storm to hit Colorado was on May 8, 2017. The Denver metro area sustained $2.3 billion in insured damage.
Here are some of the costliest storms:
July 20, 2009 - Storm hits the Denver metro area and costs $767.6 million ($845.5 million in 2015 dollars).
June 6-15, 2009 - Storm hits the Denver metro area and costs $353.3 million ($389.2 million in 2015 dollars).
July 28, 2016 - Storm hits Colorado Springs and costs $352.8 million.
June 6-7, 2012 – Storm hits the Front Range and costs $321.1 million ($330.5 million in 2015 dollars).
June 13-14, 1984 - Storm hits the Denver metro area and costs $276.7 million ($629.3 million in 2015 dollars).
July 29, 2009 - Storm hits Pueblo and costs $232.8 million ($256.5 million in 2015 dollars).
October 1, 1994 - Storm hits the Denver metro area and costs $225.0 million ($358.8 million in 2015 dollars).
September 29, 2014 - Storm hits the Denver metro area and costs $213.3 million ($213.4 million in 2015 dollars).
May 22, 2008 - Storm hits Windsor and costs $193.5 million ($212.3 million in 2015 dollars).
July 13, 2011 – Storm hits the Front Range and costs $164.8 million ($173.1 million in 2015 dollars).
7. Can a hailstorm be fatal?
The last known fatality to hail was Juan Oseguera, a Texas 19-year-old. However, the meteorological phenomenon claims lives across the world each year.