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Hydrologic Outlook
National Weather Service Great Falls MT
1203 PM MST Thu Feb 20 2025

...Ice Jams and Localized Lower-elevation Flooding Possible...

Warming temperatures through the weekend and the upcoming work week
will lead changes in river ice conditions and an increased risk of
river ice break-up and the potential of ice jams. Lower elevation
snowmelt and still frozen ground could also lead to some increased
runoff into creeks and rivers, adding to the potential for river ice
breakup. Ice jams are unpredictable and flooding can rapidly occur,
so those with interests along waterways should monitor water levels
over the coming week and take action should flooding occur.

In addition, frozen ground after a prolonged cold period and melting
snow may result in standing water in areas of poor drainage. This
could create difficult access to fields and impact some rural roads.
As temperatures warm further early next week and the ground begins
to thaw, muddy conditions may create additional impacts. The
greatest risk for overland impacts from snowmelt look to be from
eastern portions of Teton and Pondera counties across portions of
Cascade and Chouteau counties and most lower elevation areas in
Judith Basin and Fergus counties, where water equivalent in the
lower elevation snowpack ranges from around 1.0" to as much as 3.0
to 4.0" in portions of Fergus county. These areas are also most
susceptible to overnight temperatures remaining near or above
freezing this weekend into early next week. Across southwest MT,
there is significant water content in the snowpack in the Gallatin
valley, however melting will likely be slower with overnight
temperatures continuing to fall below freezing.

Stay tuned to the forecast for the latest temperature trends, along
with any warnings or advisories that may be issued. Please report
any flooding to local law enforcement. Do not drive over flooded
roadways as the roadbed may be washed out. Turn Around, Don`t Drown.

$$