A more rare occurrence from thunderstorms, but just as dangerous, is hail. Hail is a form of precipitation that occurs when updrafts in thunderstorms carry raindrops upward into extremely cold areas of the atmosphere where they freeze into balls of ice. Hail can damage aircraft, homes and cars, and can be deadly to livestock and people.1 Luckily, hail only forms in a thunderstorm, meaning we can be prepared if we know a thunderstorm is approaching.
Hail is responsible for over $1 billion in crop and property damage every year. Larger hailstones can fall at speeds over 100 mph, and cause damage to homes, vehicles, livestock, plants, and people. Although fatalities from hail are rare, they can cause injury if you are caught outside during a hail storm. There are about 24 people injured from hail every year in the United States.
Typical Damage from Hail:2
- Quarter-size (1 inch) – Damage to shingles
- Golf ball (1.75 inches) – Dents on cars
- Baseball (2.75 inches) – Windshields smashed
- Softball (4.5 inches) – Holes in roofs
Nebraska, Colorado, and Wyoming usually have the most hail storms. The area where these three states meet – “hail alley,” averages seven to nine hail days per year. 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. Other parts of the world that have damaging hailstorms include China, Russia, India and northern Italy.1
Hail is formed during a thunderstorm, when water droplets are lifted by the updraft of the thunderstorm to air that is below freezing temperatures. This water becomes ice, and starts to fall before it is swept up again, adding more ice and moisture every time this happens. Eventually, the hailstone gets too large and heavy for the updraft and falls to the ground.
Be Weather Alert
Hail can be seen on doppler radar, though it usually looks like an area of dense, heavy rain. Newer technology used by the National Weather Service, called dual-polarization radar allows the radar system to send out both horizontal and vertical pulses, so it is able to produce a 3-dimensional image of what is going on in a thunderstorm. Because of this, meteorologists are able to measure the size and shape of objects that it detects, including if there is hail and what size it is.
There are no specific watches or warnings for hail in particular, but because it only forms in a thunderstorm, those watches and warnings would include information about any potential for hail. If there is hail, a thunderstorm is automatically categorized as severe. Check your weather and keep a watch for the potential for hail in your area. Any thunderstorm is capable of producing hail if the conditions are right.
During a Hail Storm and After
Just as when any severe weather threatens, go inside. Do not stay outside during any severe weather event and risk injuring yourself. Hail can cause severe damage to your property, and to yourself. As stated, any thunderstorm can produce hail, so take the same precautions you would during a thunderstorm as hail is possible. Larger hail could penetrate through a small shelter, especially those without a sturdy roof. Get into a sturdy building with a good, solid roof overhead.
If you know there is a thunderstorm heading your way that is producing hail, and you have time, try to move anything that can be damaged under cover. Keep your vehicles in the garage to eliminate the possibility of hail damage to your vehicles. When we see a severe thunderstorm warning, and the warning notes that it is producing hail, we will also go move our grill under cover of the porch to keep that from getting damaged. You could also move any potted plants under shelter, because hail can damage plants as well.
When it starts to hail in your location, you should also assume there is a high chance that a tornado is close. The same updrafts that create hail are usually responsible for tornado formation as well. Stay indoors, in an interior room on the lowest level with no windows. Have your In-Home Emergency Kit ready to go before severe weather strikes so you can be prepared.
I personally have only seen hail a few times in my life. Florida is the top place for thunderstorms, but hail doesn’t usually fall there because of the warmer temperatures and the fact that it is so close to sea level, meaning the freezing temperatures are much higher from ground level than they are in other areas of the country. But that isn’t to say that I haven’t seen it. Thankfully, the few times we’ve had a storm with hail, we have been home and inside, and also had our vehicles parked in the garage (like we always do) so we didn’t have any real damage. I’ve only ever seen very small hailstones falling.