Heavy Snow Burying Northern Rockies This Morning
UPDATED 5:45 AM MDT, September 26, 2013
UPDATED By WeatherBug Meteorologists, Andrew Rosenthal and James West
A powerful early-season snowstorm is making travel difficult, if not impossible, across western Montana and adjacent portions of Wyoming and Idaho this morning. Heavy snow is falling across the higher elevations and accumulations could approach record levels by the time the snowflakes stop flying later today.
An unusually potent low pressure system moving from the Dakotas into the Canadian prairies is pulling down cold, Canadian air into its western flank across northern Idaho`s Bitterroots and Montana`s southwestern mountains. Teaming up with an equally potent upper-level low pressure delivering a dose of Pacific moisture, the storm is squeezing it all out as an arcing band of heavy, wet snow.
Winter Storm Warnings and Winter Weather Advisories remain in place from parts of Idaho`s Sawtooth mountains into southwestern and west-central Montana`s mountains through this evening, including Challis, Idaho, and Butte, Great Falls and Bozeman, Mont. Additional Winter Storm Watches are in place for Wyoming`s northwestern mountains from Thursday night into early Friday.
Areas above 5,000 feet are sitting right at the freezing mark, allowing a bounty of moisture to fall as heavy snow across the higher terrain. This means accumulating snow for cities such as Butte and Dillon, Mont., and heavy snow for the high-elevation locations, including many of the mountain passes.
Nine inches of snow has fallen at Heart Butte, Mont., with Basin, Mont., seeing 4 inches just this evening. Togwotee Pass, Wyo., has measured a foot of snow. Another 5 to 10 inches of snow will fall through this evening, bringing totals to around a foot for many areas of the higher elevations.
The snow and its coming dreams of winter aren`t all good news. Numerous high-elevation passes closed due to the adverse conditions, and Beartooth Pass through Yellowstone National Park remains closed this morning. Although it was previously closed, Macdonald Pass (U.S. Route 12) still has chain requirements in effect. Anyone planning to drive across the passes today should be prepared for road closures, and have chains in the vehicle. Also, be sure to pack a winter supply kit, consisting of water, food, shovels and blankets.
In addition to the driving dangers of the snow, there is a concern for power outages. The heavy, wet nature of the snow will weigh down trees, particularly those that still have their leaves, snapping branches that will in turn fall on power lines.
The early-season winter storm could rank in the top 10 for September daily snowfall. The highest September accumulation at Butte, Mont.`s Bert Mooney Airport, at an elevation of 5,545 feet, is 6.9 inches on September 24, 1920. The greatest September snow at Leadore Cooperative station in Idaho, at 6,700 feet, is 4 inches set in September of 1968.
As the moisture slips southward, it will be a similar story for snow-lovers across Wyoming`s Teton mountains tonight and Friday. Although it will start as a chilly rain for most, cold air funneling into the low`s backside will squeeze out as much as a foot of new snow. In fact, as much as 16 inches could fall along the favored eastern slopes of Wyoming`s northwestern mountains.
Be sure to keep WeatherBug active to receive the latest weather in your neighborhood and get the latest updates anywhere on Twitter
What do you think of this story?
for comments or suggestions.