Hail? Yes …

7 years ago

Here in the County, we sometimes see ice in the summertime. And probably every County resident has seen it at one time or another. Of course, I’m talking about hail. Hail can ruin a garden, lickety split.

Hail can also cause severe property damage, as happened a number of summers ago up in the Valley, when many of the car dealers were hit hard by up to golfball-sized hail.

Now, sometimes, when listening to or reading a weather forecast, you may hear the term “small hail”. Well, small hail can still be pretty big. The large hail definition starts at one inch diameter, which is the exact diameter of a US Quarter. So just a slight reduction in diameter, and if officially would be called small hail. Many people hear small hail and think “no larger than peas”, but that is certainly not the case.

Though I’ve written of this next hazard before, perhaps some missed that column, and it is so, so important to know. Flash flooding is every bit as lethal, in terms of annual fatalities, as lightning.

In the weather course I teach at UMPI, I show videos of vehicles driving across roads with water about halfway up the wheel, flowing at a good clip. The vehicles never make it to the other side. You can look for yourself, just google on “cars swept off of roads” and then click “videos” and you will see the danger yourself. If you have children who will be driving in a few years., you should watch some of the videos with them. They need to see what can happen.

The phrase used by all meteorologists is a good one, and easy to remember: TURN AROUND, DON’T DROWN. Never cross a flooded roadway. Not only could you be swept off it, the roadbed itself may already be washed out.

Flash flooding can develop either locally, from thunderstorms, or sometimes it can be more widespread with a larger scale system, such as the remnants of a tropical storm or hurricane.

Given that we are at the height of camping season, it’s worth mentioning that, over the years, there have been some backcountry tragedies involving tents pitched in or near dry riverbeds. Flash flooding can and does occur without a single drop of rain falling in some of the areas affected. How? Because it may absolutely pour upriver. And the water will come rushing down your “dry riverbed”. Be dialed in to the night sky when camping. If you are out of range of a tower and have no signal, and thus can’t look at radar, just watch the sky. Look for  any distant flickering. Pay attention if the flickering gets more frequent. If camping, pay especially close attention if that flickering is coming from the direction of higher terrain.

One of the most horrifying flash floods occurred in the Big Thompson Canyon, in Colorado, on July 31st of 1976. The canyon was filled with with people celebrating Colorado’s 100 years of statehood. That evening, a moist, easterly flow of air from the Great Plains, allowed huge thunderheads to develop, and the flow essentially locked them in place. against the Front Range of the Rockies. One of these towering monsters dumped about ONE FOOT OF RAIN on the headwaters of the Big Thompson River in less than 4 hours. Very little rain fell on the lower part of the canyon, where most of the unsuspecting victims were. A 20 foot wall of water came screaming down the canyon at mid-evening, killing 144 people, with one body washed 25 miles out into the Great Plains. Unfathomable.

Ted Shapiro holds the Broadcast Seal of Approval from both the American Meteorological Society and the National Weather Association. An Alexandria, Va. native, he has been chief meteorologist at WAGM-TV since 2006. Email him at tshapiro@wagmtv.com.