Last Sunday night, Sept. 18, a thunderstorm of a relatively small size, but rather intense, moved across the Coeur d’Alene area. There were numerous flashes of lightning, loud thunder and pockets of heavy rainfall. The heaviest precipitation was seen across Lake Fernan as .27 inches of rain fell in about 40 minutes. Coeur d’Alene only received .09 inches from that system. Many towns outside of this small, but strong storm only reported a few showers.

As we move farther along into the fall season, the odds of seeing these thunderstorms in our region will decrease. However, there have been instances of these types of storms during the fall and even in the winter season. Cliff and I have seen lightning and heard the thunderous booms during a winter snowstorm in our region. This phenomenon is called a “thundersnow.” These types of snowstorms accompanied by thunder and lightning are different than the thunderstorms we often see during the spring and summer months.

For example, during the warmer seasons, there are rising updrafts of warm, moist air near the surface that can go as high as 40,000 feet. The collisions between the warm and moist air with the cooler air from the north can often lead to thunderstorm activity, especially during the spring season here in the Inland Northwest.

With snowstorms, the upward and downward motions of air is not nearly as strong. However, when some of these cold storms move over the warmer lakes, like Lake Coeur d’Alene, Hayden Lake and others, the air can be heated and create more of an updraft resulting in rare occasions of thunder and lightning.

It’s almost hard to believe, but there are about 25 million lightning strikes per year in the U.S. There are an average of 49 people killed and hundreds more injured from this phenomenon. So far, according to the National Weather Service, there has been about 35 people killed this year from lightning.

When teaching my Physical Geography course at North Idaho College, students will ask about lightning, such as its length and width. According to a lightning expert, Martin Uman, of the University of Florida’s Lightning Research Group, the average lightning bolt is only about an inch wide (yes, only an inch) and approximately 5 miles long. There are an average 3-4 strokes within a bolt of lightning. By the way, the temperature of a bolt of lightning is around 40,000 to 50,000 degrees Fahrenheit, which is hotter than the surface of the sun.

In a new report recently released by the World Meteorological Organization, the world’s longest lightning bolt was reported over Oklahoma back in 2007. It traveled a whopping 199.5 miles and the flash lasted 7.74 seconds. Most lightning flashes are less than several seconds. This record was the first time that lightning was included in the World Weather and Climate Extremes Archive. These documents include records for heat, cold, rainfall, snowfall and other weather extremes.

The World Meteor-ological Organization says that the advancement of lightning-sensing technologies now make it possible to detect more accurate lightning measurements. It allows scientists to study specific flashes in more detail.

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In terms of our local weather, with the dry and warm temperatures expected this week, don’t be surprised to see a thunderstorm develop as storm systems are expected to arrive during the normally wet “new moon” lunar phase of Sept. 30 through Oct. 8. And, this cycle may be cold enough to produce some flakes of snow over the higher mountains to the north and east of us early next month.

Once we get through the next wet period across the region around the second week of October, we’ll probably turn dry with chilly temperatures. This would be the time period that favors readings at or below freezing past Coeur d’Alene. We’ve already seen temperatures at or below the freezing mark earlier this month across the Panhandle of Idaho. To the east in Montana, there have already been widespread frosts with snow in the higher mountains.

But, to the east, there has been flooding rains in the center of the country with drought conditions near the East Coast. More on that next week.

As we’ve been mentioning for quite some time, the upcoming winter still looks snowier than usual, despite a La Nada-type pattern, the in-between warmer El Nino and cooler La Nina sea-surface temperature pattern. Some of our snowiest winters have occurred during a La Nina event.

There may be some snowflakes in the lower elevations by late October, but the heavier stuff is not expected until at least the early to mid portion of November.

Contact Randy Mann at randy@longrangeweather.com