Why our winds have increased since 2007

Debbie Mann, no relation to Meteorologist Randy Mann, asked me a couple of weeks ago to explain why our winds have increased in strength in the past few years.

Well, Debbie, since 2007, we've had a series of stormy years across the Inland Northwest, including the all-time snowiest winter season in 2007-08, when we gauged an all-time record 172.9 inches of snow and 2012, which was Coeur d'Alene's wettest year since 1895 with an incredible 43.27 inches of liquid precipitation.

The reason that we've seen higher winds is simple. We've had far more storms than usual in recent years. More storms equal more winds.

First and foremost is 'air pressure,' the difference between the pressure in one place and the barometric pressure in another. The bigger the difference between the two, the stronger the winds, especially at the surface. Remember, "Nature abhors a vacuum."

The second force that shapes the wind is 'friction.' We may not realize it, but flowing air is greatly effected by friction as it travels across the changing topography of a given region, somewhat like water flowing over a rocky river bottom. Air gets slowed down and pushed around by just about everything it runs into including trees, buildings, mountains and roadways.

The third effect is the Earth's 'rotation,' which causes winds to bend and change direction. The paths are often radically different from what we would see happen from just the influence of barometric pressure and friction.

The steering effect, called the 'Coriolis Force,' pushes winds to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. That's why most of our storm systems from the Gulf of Alaska and the Pacific Ocean regions tend to travel from northwest to southeast across the country.

To sum things up, our winds have increased in recent years due to intense storminess linked to 'La Nada' and 'La Nina' sea-surface temperature events, the cutting down of many former tree 'windbreaks' and various other manmade changes to the general topography of our region.

Changes in windflow cycles or patterns are, like so many other climate factors, directly related to ever-changing cycles of heat energy from the Sun. The more intense the heat energy, the stronger the winds will be, especially during the stormy periods.

As the song goes, "the answers, my friends, are blowing in the wind."

NORTH IDAHO WEATHER REVIEW AND LONG-RANGE OUTLOOKS

April of 2013 locally, as well as nationally, was another month of wide weather 'extremes.' Overall, the month of 2.6 degrees cooler than usual. Oddly enough, our warmest afternoon was April 1 with 74 degrees. We saw a record low of 22 degrees on Player Drive on April 17.

Our snowiest day was April 30 with a surprising 0.3 inches of the white stuff being gauged late in the afternoon on Tuesday. The record snowfall for the date was 0.4 inches in 2002. Our total snowfall this April was a puny 0.4 inches, below the 118-year normal since 1895 of 0.7 inches. Last year, in 2012, we had 3.3 inches of snow.

Our total snowfall for the 2012-13 winter season, as of this Thursday, May 2 writing, stood at 73.6 inches, 3.8 inches above normal, but nearly 10 inches less than the 83.4 inches that we gauged last winter in 2011-12. This next winter season of 2013-14 may turn out to be much snowier than usual, if we do see Randy's predicted arrival of another cold and wet 'La Nina' sea-surface temperature event in the cooling waters of the eastern Pacific Ocean.

Our total liquid precipitation this April in Coeur d'Alene was 2.13 inches. This included a record .58 inches of rainfall on April 19. There were three days during the 30-day period with thunderstorm activity. Our normal April precipitation since 1895 has been 1.77 inches.

The 'good news' was the fact that we saw 46 hours of sunshine this April more than usual and a whopping 84 hours more than we observed last April in 2012 during the wettest and coolest spring in the record books.

The month of May began on a frosty note on Wednesday. We logged a frigid 29 degrees on Player Drive, where 'traces' of snow remained on the ground from the 'rare' April 30 snowstorm. Remember, even in May, there are times that we need to cover those sensitive plants.

Our long-range outlook through mid June hasn't changed. We're still calling for 'sun and showers.' The summer of 2013 still looks GREAT weatherwise. We see LOTS OF SUN and LITTLE PRECIPITATION to mar our outdoor activities.

Cliff Harris is a climatologist who writes a weekly column for The Press. His opinions are his own. Email sfharris@roadrunner.com