Prepare and Be Aware: Overland and Ice Jam Flooding Possible This Weekend

The Billings office of the National Weather Service (NWS) wants to give everyone a heads up about an unusual flood situation that is developing for this weekend. Although it is early February and despite the recent warmth, there are still pockets of snow and frozen ground across the forecast area (in Billings, NWS measured 8 inches of frost depth recently). A storm system is expected to bring mainly rain and melting snow to the area from late Friday through Sunday (maybe Monday) for elevations below 5000 feet. We can't rule out rain and melting snow in the foothills up to about 7000 feet where the snowpack is thicker. Any rain/melting snow will rapidly runoff as it can't soak into the frozen or snow covered ground. This will increase the threat of overland flooding of roads and structures. As the melt water reaches streams it will increase the threat for ice jam flooding. This unusual February storm may bring a quarter of an inch up to half an inch of rain/melted snow to much of the area this weekend.

There are a lot of variables in the current forecast scenario, and flooding is not imminent at this time. The severity of any flooding impacts will be determined by where and how much precipitation falls, how much is rain/melted snow, and the state of the frozen ground. Now is the time to take precautions to prevent damage and to raise awareness.

KEY POINTS

• Unusual February storm system to bring rain/melting snow to the region this weekend

• Precipitation will rapidly runoff due to frozen ground and snow cover increasing flood threat

• Overland flooding of roads and structures (basements) is possible but not imminent at this time

• Any runoff will increase the threat of Ice Jam flooding on creeks and streams

• This is the time to take precautions to prevent damage to livestock and property