Weather Prediction Center

National Oceanic and Atmospheric Administration

Winter Storm Severity Index (WSSI)

The WSSI does not depict official warnings and should always be used in context with official NWS forecasts and warnings. For a users guide and more information about the WSSI, please select from the dropdown menu below.

Product/Service Description Document WSSI Fact Sheet WSSI Infographic WSSI Users Guide Interactive ESRI Story Map WSSI Future Work Video Guide

*NEW* Rolling 24 HR WSSI Display located here

Overall Impact: Maximum impact from any of the components.

Snow Amount: Potential impact from snow amount and snow rate.

Snow Load: Potential impact from the weight of snow on structures.

Ice Accumulation: Potential impact from the ice accumulation and wind.

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

Blowing Snow: Potential impact from falling snow combined with wind.

Ground Blizzard: Potential impact from snow on the ground combined with wind.

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Download Latest WSSI in GIS Format:

Download Data in KML

Download Data in SHP

*NEW* WSSI Static Image Archive:

WSSI Static Image Archive Data

Map Overlays
NWS County Warning Areas		River Forecast Center Boundaries
FEMA Boundaries		Counties Boundaries
State Boundaries		NWS Public Forecast Zones
Urban Areas		ARTCC/FIR

Retrieve Static Images

Select Zoom Area

Select WSSI Element
WSSI Overall	Blowing Snow	Flash Freeze	Ground Blizzard
Ice Accumulation	Snow Amount	Snow Load

To retrieve static images please select a zoom area and WSSI element.
*Please Note* Static images only update at 01, 09, 13, 19 and 21 UTC

Day 1

Day 2

Day 3

Days 1 - 3

Weather Prediction Center National Oceanic and Atmospheric Administration