Large hail a rarity in North Idaho
Several weeks ago, I wrote about our thunderstorm season. So far, we haven’t seen any thunderstorm development across the Inland Northwest. All the severe weather has been over the southern U.S. as three tornado outbreaks have been reported for the 2019 season.
Although we do see a number of strong thunderstorms that develop in the spring and summer months, large-sized hail is rare in this part of the country. However, in July of 2006, a severe thunderstorm flooded parts of Spokane and areas to the north of that city, but barely missed Coeur d’Alene. To the west, golf ball-sized hail was reported in the Post Falls region.
There were many reports of damaged gardens, as flowers were literally “flattened” on the western edges of Kootenai County by the fast-moving storm, which pushed northward into Canada in a matter of a few hours.
Cliff tells me that the largest hailstone that he’s ever measured during his nearly 53 years of watching local Inland Northwest weather daily in Whitefish, Mont., Hayden Lake and Coeur d’Alene was a 3.1-inch tennis ball-sized stone. He photographed the large chuck of ice on his front porch in Whitefish on June 2, 1971.
This was the same day that Coeur d’Alene gauged a record rainfall total for the date of 1.41 inches. Fortunately, only pea-sized hail was reported in early June of 1971. That damaging hailstorm in Whitefish 35 years ago, however, cost him several hundred dollars in broken windows on the south side of his small house on Jennings Avenue.
On average, Coeur d’Alene and surrounding regions usually have just three or four days a year with hail, mostly small pea-sized, but there are rare occasions when hailstones will be the size of golf balls, as was the case back in 2006.
Hail will consist of balls or irregular lumps of ice that will form in thunderstorm-type clouds called cumulonimbus. It forms when there are strong, upward motions of air and the water in the cloud will freeze as it moves up into the cloud. With updraft wind speeds as high as 110 miles per hour, the hailstone can move up and down in the cloud. As it descends through the cloud, it receives another layer of supercooled water droplets. As it moves up the cloud, the water droplet freezes once again and the hailstone becomes bigger. The ball of ice falls to the ground when it becomes too heavy in the cloud.
According to Wikipedia, the heaviest hailstone was 2.25 pounds and fell at Gopalganj District in Bangladesh on April 14, 1986. The largest diameter officially measured was 7.9 inches at Vivian, S.D., on July 23, 2010. That particular hailstone had a circumference of 18.622 inches. But, the largest circumference, the distance around the ice, was 18.74 inches, which fell at Aurora, Neb., on June 22, 2003.
The place that experiences the most hail on average is in Kericho, Kenya, in Africa. Approximately 50 days a year this region sees that type of weather. Kericho is close to the equator and is in the mountains at around 7,200 feet. This place also holds the world record for most days with hail as it received 132 days in one year.
Hailstorms normally last only a few minutes, but often cause widespread damage, especially east of the Rockies where hailstones can become quite large. If a thunderstorm were to get stuck over an area, there can be hail that accumulates. On July 29, 2010, a stalled thunderstorm dropped over a foot of hail in Boulder City, Colo.
The peak for hail in the U.S. is in June and occurs most often in the Great Plains and the western portions of the Midwest. It’s estimated that damage alone from hail is over $1 billion each year.
According to NOAA’s Severe Storms, there was over 6,045 major hailstorms in 2017 that resulted in nearly $2 billion in property and crop damage. In 2018, there were 4,610 major hailstorms in the U.S. Texas had the most last year with a total of 508. Idaho had 34 hailstorms, mostly in the southern part of the state, while Washington had only 1.
In terms of our local weather, we’ll still have a mix of sun and showers, but there we should see more widespread rainfall toward the end of the month. There’s also the possibility of a few snowflakes during the overnight hours from this system.
April will finish with above-normal moisture as we’ve had close to 2.75 inches at Cliff’s station. The normal for April is 1.77 inches. Rainfall is expected to increase in late April and early May across the region. Next month should have near- to above-normal moisture, but conditions should eventually turn drier than average later in the spring and summer season.
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Randy Mann can be reached at randy@longrangeweather.com