Weathercatch: When hail freezes over – and it’s July

Seven years ago tomorrow, a swarm of thunderstorms rolled across the Inland Northwest, producing brief heavy rains, strong winds and some golf-sized hailstones that left a trail of damage. Sunny skies and warm temperatures preceded the storm outbreak. After all, it was July.

Before we get to those turbulent storms from seven years ago, let’s talk about hail. Though it hasn’t hailed so far this July, it could if the right storm system rolled through. In fact, hail is a common atmospheric phenomenon during summer .

Hailstones are balls of ice, so how can they form when it’s the peak of summer?

It all begins with a humble raindrop.

Rising air in a thunderstorm – known as an updraft – vaults summertime raindrops high into a towering cumulonimbus cloud where temperatures are below freezing. This causes the water droplets to freeze into crystals that accumulate layers of ice as they get tossed about thousands of feet aloft. The stronger the updraft, the bigger the hailstones can grow as they collide with other raindrops that freeze to them on contact. Because of this ice layering, a series of concentric rings exist inside a hailstone, similar to those inside an onion.

Because what goes up, must come down, hailstones fall when their weight overcomes the strength of the updraft or the updraft simply weakens.

Falling at high speeds and often accompanied by wind gusts, hail can look, sound and feel as if the sky is falling when it hits the ground. Small pellets make a loud clacking sound and sting when they strike our skin. The larger ones can break glass, dent cars, shred crops, punch through screens and injure and even kill animals and occasionally humans.

Typical hailstones fall at a speed between 25 mph and 40 mph, according to NOAA’s National Severe Storms Laboratory. They are usually pea-to-marble-sized, while more severe thunderstorms with stronger updrafts tend to produce larger hailstones, according to the agency.

Like those that pummeled parts of the Inland Northwest on July 23, 2014. The weather had been warm and sunny that day, with temperatures in the mid-80s. Early that afternoon, the National Weather Service placed Spokane, Coeur d’ Alene and other communities in Eastern Washington and North Idaho under severe thunderstorm warnings.

The first in the storm series arrived shortly after 4 p.m., unloading hailstones the size of golf balls in Pomeroy and only slightly smaller in Pullman and Palouse. About that same time, another storm hit northwest Spokane, bringing high winds and nickel-sized hail. Eighty miles away, yet another strong storm struck Kettle Falls, where 2-inch hailstones pounded sidewalks, homes and cars.

With “wind gusts up to 75 mph and hail up to 2 inches” the National Weather Service Spokane reported that the thunderstorms “produced injuries from falling debris, destroyed or damaged several homes and knocked out power for 67,000 people,” adding that 44 mobile homes were damaged or destroyed by falling trees.

It’s interesting to note that it was 84 degrees in Spokane when the first storm arrived around 4 p.m. However, by 5 p.m., it was 64 degrees. A 20-degree drop in one hour is unusual for the Inland Northwest. It also underscores the potency of the passing storms.

While the idea of tumbling ice balls sounds like a refreshing break from our prolonged spell of record-breaking hot, dry weather, keep in mind the damage they can inflict. Fortunately, hailstorms aren’t as common here as in the southern and central plains states, where Nebraska, Colorado and Wyoming top them all, according to the severe storms laboratory. “The area where these three states meet – “hail alley” – averages seven to nine hail days per year,” the agency states.

If you think golf ball-sized hail sounds big, consider that the largest hailstone recorded in the U.S. was the size of a volleyball. Eight inches across and 18.62 inches in circumference, it fell in Vivian, S.D., on July 23, 2010.

And that, dear readers, was 11 years ago tomorrow.

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Nic Loyd is a meteorologist in Washington state. Linda Weiford is a writer in Moscow, Idaho, who’s also a weather geek. Contact: ldweiford@gmail.com