For Your Information
For Your Information
If there is something that may be of interest to you, we will try to make that information available.
 
Scaled Predictive Ice Storm Aftermath (SPIA) Index
 

Current National Weather Service (NWS) Ice Storm Warnings are issued based on forecast ice accumulation only, typically one quarter of an inch or greater. The combined effect of ice and wind, which more realistically describes damage potential, is not formally set as warning criteria.

 

The Ice Storm of January 26-28, 2009 was devastating in northern Arkansas. By using the Scaled Predictive Ice Storm Aftermath (SPIA) Index, the NWS should be able to provide a better understanding of ice storm impact potential to local state, and federal response entities. The potential impacts are scaled from 0 to 5 and suggest potential electrical outage coverage and duration.
In the picture: The Ice Storm of January 26-28, 2009 was devastating in northern Arkansas. This ice in Fulton County had a 6 inch circumference, which is just short of a 2 inch diameter. The photo is courtesy of Mel Coleman. Click to enlarge.

 

Scaled Predictive Ice Storm Aftermath (SPIA) Index.
In the picture: Scaled Predictive Ice Storm Aftermath (SPIA) Index.
 

Until now, the NWS has not attempted to routinely quantify the impact of ice storms. The use of this scaled index will allow the NWS to evaluate the potential of providing these specifics.

 

 

Expected impacts associated with Scaled Predictive Ice Storm Aftermath (SPIA) Index values.
In the picture: Expected impacts associated with Scaled Predictive Ice Storm Aftermath (SPIA) Index values.
 

For example, a level 5 ice storm would be defined as one causing catastrophic damage to entire exposed utility systems, including both distribution and transmission networks. An event of this magnitude could knock out power for several weeks in some locations.

 

SPIA Index Forecasts.
In the picture: Day 1 SPIA Index Forecast
NOTE: National Weather Service Little Rock County Warning Area is in green.


SPIA Index (Day 1)  |  SPIA Index (Day 2)  |  SPIA Index (Day 3)
 

The NWS in Little Rock, along with surrounding offices, has agreed to test the Scaled Predictive Ice Storm Aftermath (SPIA) Index this winter. Graphics showing forecast index values will be made available as part of the routine forecast provided online.


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.