More tornadoes than usual east of the Rockies this spring

We've had numerous destructive and deadly tornadoes already this spring east of the Rockies and it's not even mid-April yet.

As the unusually chilly air from our tenacious 'La Nina' runs headlong into a warm, moist flow from the Gulf of Mexico, strong thunderstorms occur along the frontal boundary 'clashline' producing severe thunderstorms that often lead to strong straightline winds, large-sized hail and deadly 'twisters.'

Nothing beats a tornado for out-and-out fury. While a hurricane spreads itself out over a wide area, by extreme contrast, a tornado selects a specific target and concentrates its rage on this isolated zone with all the force it can muster.

The near-vacuum interior of the tornado funnel creates a suction that has been credited with forcing pieces of straw through fences, defeathering chickens and exploding buildings.

While speeds within a tornado can reach 250 miles per hour or higher, often destroying wind-measuring anemometers, these atmospheric 'madmen' move across the ground at just 20 to 30 miles per hour, usually from southwest to northeast in the Northern Hemisphere. Too violent for longevity, the lifespan of the typical 'twister' is normally measured in minutes, not hours. However, one deadly tornado in June of 1954 survived nearly 7 hours and covered a distance of approximately 300 miles of destruction, including at least a dozen deaths.

The worst outbreak of tornadoes in U.S. history occurred on April 3 and 4, 1974, the so-called "Super Outbreak." A total of 148 twisters touched down in 13 states from Illinois and Indiana southward into Mississippi and Alabama. Over a period of 16-18 hours, a total of 330 people were killed and 5,484 persons were injured.

The property damages estimate from the April 1974 "Super Outbreak" was an incredible $600 million. The most deadly and damaging tornado ever occurred on April 4, 1974 at Xenia, Ohio. Half of the town was destroyed and property damage totals exceeded $100 million.

In an average year, there are approximately 1,200 tornadoes sighted in the U.S., more than any other place in the world. More than 60 percent of all U.S. tornadoes each year occur in what is called, "Tornado Alley," which stretches from Texas and Oklahoma northward through Kansas and eastern Colorado into Nebraska and Iowa.

On Saturday, March 26, about 150 trained storm spotters came to the University of Nebraska's Lincoln East Campus to get the latest information for the upcoming spring season. They are the ones who inform the National Weather Service and other media when the tornadoes touch down in a particular area.

These people are called "hams." Most have voluntarily participated in storm chasing for over 30 years.

Compared to normal, the last several years have had a decrease on tornadic activity. However, the 2011 season, according to some scientists, "could bring much different conditions." With a weakening La Nina and colder air continuing to move southward from Canada, the chances of severe weather conditions in the Great Plains, Midwest and South are higher than usual.

Fortunately, North Idaho does not have hurricanes and experiences only the 'rare' tornado, typically one that causes just minor damage and few injuries. That's another reason why I live here, folks.

NORTH IDAHO WEATHER REVIEW AND LONG-RANGE OUTLOOKS

Many residents of North Idaho were shocked to see a 'winter wonderland' outside their windows early Thursday morning.

Between one and three inches of the white stuff was measured throughout the region as temperatures plunged into the upper 20s and lower 30s.

The 1.9 inches of snow that we received on Player Drive on April 7 broke the record for the date of 1.2 inches set back 82 years ago in 1929.

April's total snowfall as of 10 a.m. on Thursday was 2.7 inches, more than four times the normal puny 0.6 inches usually received during the entire month in the Coeur d'Alene area. The all-time record April snowfall of 8.2 inches in town was set nearly a century ago in 1920.

Our seasonal snowfall as of 10 a.m. on Thursday reached 116.1 inches on Player Drive, some 46.3 inches above the normal snowfall for a season ending June 30 of 69.8 inches. Last winter, during a warm and rather dry 'El Nino' event in the waters of the Pacific Ocean, we only gauged 18.4 inches of snow by the end of June in 2010. However, back-to-back, the winters of 2009-10 and 2010-11 will be near-normal in total snowfall for the 24-month period, from 'famine' to 'feast' at 134.5 inches. The normal two-year snowfall would be 139.6 inches.

As of Thursday, April 7, at 10 a.m., our annual precipitation in Coeur d'Alene had risen to a near-record since January 1 of 13.06 inches. Only soggy 1974 with 13.88 inches for the period was wetter in town.

The number of days since March 1 with measurable precipitation in Coeur d'Alene was 30 for the 38-day span, 24 in March and 6 out of 7 days thus far in April. This was a new record for continuous wetness, beating out 28 days in a similar period in 1916.

It looks like a cooler and wetter than normal April and early May across North Idaho and the Inland Empire. There will, however, be some occasionally sunny days with mild temperatures. But, there could still be some rather 'rare' spring snowflakes in the air, especially early in the period.

Longer-term, Randy Mann and I are still hopeful that we'll see a warm and dry summer season in 2011 as 'La Nina' finally dies off in the tepid waters of the Pacific.

A very strong stationary ridge of high pressure could begin in June lasting through July, August and at least early September. This should mean lots of 'Sholeh Days' this summer with afternoon highs near or above 90 degrees. At least three or four days may see afternoon maximum readings near or above the century mark in the Inland Empire.

But, if we do see unusually hot, dry and windy weather this summer, it could spell BIG TROUBLE for this region's parched grasslands and forests. Fires could rage over wide areas of the Far West later in the season. Stay tuned.

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