The Sperry–Piltz Ice Accumulation Index, or SPIA Index, is a forward-looking, ice accumulation and ice damage prediction index that uses an algorithm of researched parameters that, when combined with National Weather Service forecast data, predicts the projected footprint, total ice accumulation, and resulting potential damage from approaching ice storms. It is a tool to be used for risk management and/or winter weather preparedness.
The index is named after its co-developers, Sidney Sperry of the Oklahoma Association of Electric Cooperatives and Steven Piltz, meteorologist-in-charge at the National Weather Service in Tulsa.
The map shows intensity of the ice storm on a scale from 0 (little impact) to 5 (catastrophic damage). The index incorporates measures of rainfall (as ice), wind, and temperatures to come up with an aggregate measure. Washtenaw County's forecast is a 0, but to the north (Livingston) and west (Jackson) counties there are chances for more severe icing. The forecast gives the worst hit to upstate New York along Lake Ontario; alas this map does not show Canadian forecasts, but news accounts predict severe weather in Toronto as well.
A report from Brampton, Ontario:
Ice in Burlington, Vermont:
Power outage map (Sunday a.m.) from DTE Energy:
Power outage map (Sunday a.m.) from Consumers Energy:
Ice estimate from National Weather Service Detroit: