The Bitterroot Valley started out the new year around 20% below average in snowpack. Then came the snows of February. It was a lot of snow and a lot came down all at once over a couple of days. It turns out, by March 1, it was enough to bring the Bitterroot back up to about an average snowpack. Actually, a little bit above, at 103% of average. Historically, Montana has accumulated about 80% of its total snowpack by March 1.
The Bitterroot Valley wasn’t the only area to be so affected. According to snow survey data collected by the USDA Natural Resources Conservation Service (NRCS), snowfall for the month was above normal to record setting across the state, and snowpack totals for March 1 have improved in all river basins.
Lucas Zukiewicz, water supply specialist with NRCS, said, “It seemed like every time a storm was moving out another one was lined up to come in.” Monthly totals were especially impressive in some southern and central regions of Montana, including the Bitterroot.
“This month was the perfect setup with cold air in place and abundant moisture coming from the Pacific that collided with it,” said Zukiewicz. “Sixteen NRCS snowpack measurement locations set new records for February snowfall in central and southern Montana, and an additional 13 sites recorded the second highest monthly totals.”
While improved snowpack totals and above normal totals in certain rivers basins is good news for this date, there is still plenty of winter and spring left to come. Snowpack in the state typically peaks in early April west of the Divide and in mid to late April east of the Divide. “We have another month or two of snow accumulation to go, and it can be an important couple of months to top things off before we start to see snowmelt and runoff,” said Zukiewicz. “We’re back on the right track, so let’s hope that the snow keeps flying and the above average temperatures don’t show back up before then.”
Luke Robinson at the National Weather Service office in Missoula agreed, adding that based on current weather forecasts, there currently was not much chance of any major flooding along the rivers for another couple of weeks. He said it would take a warming trend with above freezing temperatures at night with some rain to bring the snow down out of the mountains in any major way. Right now, he said it was too far off to predict what that runoff would be like, but in the short-term things look pretty good as far as the current melt off of low-lying snowfields on the valley floor.
According to Robinson, the daytime temperatures are forecast to be in the high 30s and 40s during the day and dip below freezing at night for the next several days. This will result in a gradual melt-off during the day that will stop at night, making for a slow release of the 2 to 4 inches of water contained in the low-lying snow on the valley bottom. Streamflow forecasts issued on March 1 for April 1-July 31 indicate near to above average seasonal volumes in many areas across southern Montana but are slightly below average in some northern basins due to the early season deficits that remain in water year-to-date precipitation.
“It looks like we are turning the corner into spring,” said Robinson, “and in the near term, we are not concerned about any serious flooding from the snow melt.” Some new snow, maybe ½ to 1 inch, was expected to arrive on Tuesday and Wednesday, but the temperature regime of warm days and freezing nights is expected to continue through the week.
While no flooding is predicted in the immediate future from the river, there is still the potential for isolated flooding in areas of the valley bottom.
The Ravalli County Sheriff’s Office has issued some flood preparedness information as it is anticipated that minor flooding may occur at some locations throughout the valley, including areas adjacent to and downstream from irrigation ditches and canals, fishing access locations, culverts, bridges, small creeks and streams, and areas in which debris and/or ice has built up.
Emergency services in Ravalli County are encouraging residents and property owners to be aware of the situation and potential flooding. People who have experienced flooding in the past should prepare now by assessing their own risks and taking appropriate actions to mitigate any effects of high water. Sandbags can be placed at appropriate areas around the properties as a mitigation effort.
Sand and sandbags will be available to Ravalli County residents at the following locations:
• Corvallis Fire, Station #2 at mile marker 9 on Eastside Highway, southeast corner of the station building
• Three Mile Fire, Station #1, 1064 Three Mile Creek Road, northwest corner of the parking lot
• Victor Fire, new station building at 2383 Meridian Rd in Victor
• Stevensville Fire, Westside Station at the Stevensville Wye behind Subway
Sandbags should only be placed to protect structures and must not be used to divert water onto other properties.
Do not place sandbags, boards or other obstructions or diversions in irrigation ditches or canals. Stay clear of these areas and do not park vehicles near the ditches or on access roads.
If you have questions regarding wells or septic tanks, you may contact the Environmental Health Department at 406-375-6565.
It is very important at this time to keep the following safety messages in mind:
• Do not approach areas of high water and flooding, including fishing accesses, area streams, ditches, and the Bitterroot River.
• Ensure the safety of your children and animals by keeping them away from hazardous areas.
• Do not enter or cross flowing water or water of unknown depth.
• Observe any road closures or detours- they are in place for your safety.
Roadway hazards or flooding may be reported to the Ravalli County Road Department at 363-2733 or the Ravalli County 911 Center at 363-3033. Dial 911 for life threatening emergencies.
The Ravalli County Office of Emergency Management is monitoring the situation and coordinating response efforts with the Ravalli County Road Department, local fire districts, and other local, state and federal partners. The Office of Emergency Management may be contacted for further information during normal business hours at 406-375-6655.
Robinson, at the Missoula National Weather Service, said that snowfall during the month of February in the Missoula area did not break any records. He said the monthly total at 25.7 inches ranks as the third snowiest February on record. He noted that the Bitterroot valley got almost that much snow in two days.
“You’ve gotten a lot more snow than we have in Missoula, but we do not have the long term consistent records to determine that it was the snowiest on record,” he said. “It’s certainly above average, but we can’t say for certain that it is a record.”
The Natural Resources and Conservation Service (NRCS), however, does maintain seven Sno-Tel sites in the Bitterroot and Sapphire Mountains surrounding the valley on Daly Creek, Lolo Pass, Nez Perc Camp, Saddle Mountain, Skalkaho Summit, Twelvemile Creek, and Twin Lakes.
Although the amount of water contained in the snow – the Snow Water Equivalent (SWE) – at the sites has been recorded since 1928, records of snow depth do not begin until 2002. The relationship between snow depth and water content is not a direct correlation because the snow can be either wet and heavy with water content or dry and light in which case it reaches a greater depth but contains less water. All the sites in the Bitterroot valley are currently showing from 98% to 111% of the median snow water equivalent.
BITTERROOT RIVER BASIN – Snow Water Equivalent
Place, Elevation, SWE, Median SWE, % of Med.
Daly Creek, 5780, 10.2, 9.2, 111
Lolo Pass, 5240, 24.1, 24.6, 98
Nez Perce Camp, 650, 11.5, 12.0, 96
Saddle Mtn., 7940, 19.9, 20.5, 97
Skalkaho Summit, 7250, 18.1, 18.5, 98
Twelvemile Creek, 5600, 15.7, 14.6, 108
Twin Lakes, 6400, 35.1, 32.6, 108
Basin Index (%) 102
BITTERROOT RIVER BASIN – Total Precipitation
Place, Elevation, Precip, Median Precip, % of Med.
Daly Creek, 5780, 11.7, 11.5, 102
Lolo Pass, 5240, 27.7, 29.1, 95
Nez Perce Camp, 5650, 17.9, 17.4, 103
Saddle Mtn., 7940, 18.4, 19.7, 93
Skalkaho Summit, 7250, 18.7, 19.2, 97
Twelvemile Creek, 5600, 31.5, 27.3, 115
Twin Lakes, 6400, 37.0, 38.7, 96
Basin Index (%) 100