Summer came to an abrupt halt in parts of the Rocky Mountains on Tuesday as temperatures reaching into the 90s (Faherenheit) plunged by around 60 degrees F (over 15 degree Celsius) in less than 24 hours, with a powerful surge of cold air from Canada unleashing snow and damaging winds in several states.
The roller coaster weather ripped up trees by their roots, piled up snow that shut down parts of the scenic road through Glacier National Park and knocked out power to tens of thousands. But the temperature drop gave some relief to crews fighting wildfires in Colorado and Montana that had ballooned in hot, windy weather and forced people to flee their homes.
Snow fell in Colorado, Montana and Wyoming and forecasters predicted up to a foot (30cm) in the mountains and temperatures in the teens (-7 Celsius) overnight. “We went from record heat to snow within a matter of 24 hours,” said Evan Direnzo, a National Weather Service meteorologist in Colorado. “Any average person would see this a couple of times in their life.”
In Utah, where temperatures dropped by 40 degrees F, wind gusts of nearly 100mph roared through the Salt Lake City area, downing trees and leaving tens of thousands without electricity.
Since forecasters began keeping records about 150 years ago, a one-day change in temperature of 55 degrees F (nearly 13 degrees C) or more has occurred two dozen times in Denver, according to the NWS.
Six inches (15cm) or more of snow could fall in the northern and central Rockies, with 1 to 2 feet (30-60cm) dropping in the highest peaks, the NWS said.
It has issued scattered winter storm warnings and weather advisories from southern Montana to southern Colorado. Freeze and frost warnings also were posted for parts of Montana, Idaho, Colorado, Nebraska, North Dakota and Minnesota.
The weather was gradually expected to warm up, with temperatures back in the 80s by the weekend in Denver.