Record-breaking cold expected across Montana on Wednesday, Thursday

Record-breaking cold temperatures not seen in Montana in more than 30 years are expected statewide Wednesday night and Thursday morning as an Arctic air mass drops down from Canada. 

“We’re expecting the possibility for cold on historic proportions this Thursday — temperatures quite possibly colder than anything we’ve seen in 40 years,” said C. Corby Dickerson IV, a meteorologist at the National Weather Service in Missoula. “The time for preparation is now.”

 After several days of temperatures hovering near 0 degrees and below, moderate-to-heavy snow is expected in western and central Montana on Tuesday evening into Wednesday morning accompanied by strong northerly winds. 

By late Wednesday morning, the western part of the state could see 2-8 inches of snowfall, with higher amounts in the Missoula, Kalispell and Glacier National Park areas. Winter storm warnings and winter weather advisories are in effect into late Wednesday morning.

The broader concern will be the frigid temperatures that follow as a surface high pressure system sits over the area Wednesday through Thursday, according to the National Weather Service in Great Falls and Missoula. The airmass has already brought temperatures to -50 in parts of northwestern Canada. 

Wind chills could hit -40 degrees or colder Tuesday night through Thursday. And temperatures will be well below zero for most of the state Wednesday and Thursday. Wind chill warnings are in effect into Friday afternoon across most of Montana.

Temperatures and wind chills that cold can cause frostbite in just minutes. People are advised to limit their time outside and to wear multiple layers covering as much of their body as possible if they must be outdoors for any extended period. 

Pet owners should bring their pets inside when possible, and anyone needing to drive should have their vehicle prepared with proper safety equipment and warm clothing and blankets. 

Daytime temperatures are expected to be in the -20 to -10-degree range across most of the state Wednesday and Thursday, and lows overnight Wednesday into Thursday are expected to be in the -40 to -30 range across Montana, including some areas that will be even colder, according to the NWS. 

“It is possible some of the coldest valleys could see air temperatures colder than 50 or 60 below,” NWS Great Falls forecasters wrote in Tuesday morning’s forecast discussion. “… These records will be dependent on skies becoming clear, and any cloud cover could limit how cold it gets.” 

The National Weather Service in Great Falls said Tuesday that temperatures could be colder than some sensors can even read, as many bottom out at -40 degrees. 

Depending on where the temperatures end up, several locations across the state could break records on Wednesday and Thursday that were set more than 30 years ago. 

Many of the records were set during similar Arctic blasts in 1990 and 1983, according to National Oceanic and Atmospheric Administration (NOAA) records. For Dec. 21, record low temperatures include: 

• -32 in Helena (set in 1990) 
• -35 in Great Falls (set in 1990) 
• -41 in Bozeman (set in 1983) 
• -26 in Billings (set in 1990) 
• -39 in Glasgow (set in 1924)
• -25 in Missoula (set in 1990) 

For Dec. 22, record lows include: 

• -35 in Helena (set in 1990)
• -27 in Great Falls (set in 1892)
• -41 in Bozeman (set in 1983)
• -26 in Billings (set in 1990)
• -38 in Glasgow (set in 1916)
• -28 in Missoula (set in 1990)

Record low high temperature records may also be at risk of falling on both days if temperatures do not get above -20 degrees in some locations. 

“It’s pretty extraordinary, this kind of cold. The kind of cold we don’t see very often — possibly once or twice in a generation. For many people in Montana, [they] have never seen this kind of cold,” Dickerson IV said. 

But after the bitter cold, temperatures will warm up close to normal levels Friday and into the Christmas weekend, though strong winds are likely to create blowing snow and scattered snow showers across the state.

Saturday and Sunday’s forecast highs are expected to reach near- or above-freezing levels.