Has a tornado ever occurred at a high elevation, say in the Rocky Mountains?

Dear Tom, 

Has a tornado ever occurred at a high elevation, say in the Rocky Mountains?

—Rick Vantour

Dear Rick,

Tornadoes do occur in the Rockies, though rarely. The rugged terrain of mountainous areas usually disrupts the 10-30 mile diameter, inward-spiraling low-level wind flow in which tornadoes occur. However, they have torn across the landscape at surprisingly high elevations. The Teton-Yellowstone Tornado of July 21, 1987, offers a dramatic example of high-elevation, mountainous-terrain tornadoes. Occurring with F4 intensity, that spectacular tornado created a damage path 21 miles in length in Teton County in northwest Wyoming. It took down one million trees, mostly lodgepole pines, some of them 100 feet in height, and crossed the Continental Divide at an elevation of 10,072 feet. No one was injured, but it is the strongest tornado ever to occur in Wyoming.