Winter Storm Severity Index

These graphics are created by the National Weather Service. The WSSI does not depict official warnings and should always be used in context with official NWS forecasts and warnings. For more information, please refer to the following links: Product/Service Description DocumentWSSI Users GuideInteractive ESRI Story Map, WSSI Future Work

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Legend

No Impacts
Impacts not expected
Limited Impacts
Rarely a direct threat to life and property. Typically results in little inconveniences.
Minor Impacts
Rarely a direct threat to life and property. Typically results in an inconvenience to daily life.
Moderate Impacts
Often threatening to life and property. Typically results to disruptions to daily life.
Major Impacts
Extensive property damage likely, life saving actions needed. Will likely result in major disruptions to daily life.

Extreme Impacts
Extensive and widespread severe property damage, life saving actions will be needed. Results in extreme disruptions to daily life.

Impact Types

Overall

Maximum impact from any of the components.

Day 1 Day 2 Day 3

Blowing Snow

Potential impact from falling snow combined with wind.

Day 1 Day 2 Day 3

Flash Freeze

Potential impact from rapid decreases in temperature from above to below freezing with the presence of liquid water.

Day 1

Ground Blizzard

Potential impact from snow on the ground combined with wind.

Day 1 Day 2

Ice Accumulation

Potential impact from the ice accumulation and wind.

Day 1 Day 2 Day 3

Snow Amount

Potential impact from snow amount and snow rate.

Day 1 Day 2 Day 3

Snow Load

Potential impact from the weight of snow on structures.

Day 1 Day 2 Day 3