Earlier this winter, Weather.com posted an article about a new index to rate ice storms. Setting aside the illiteracy of the author (the article talks about how the index was used experimentally in 2009), it’s a good introduction to a new-to-me index that can help meteorologists communicate impacts to the public. The Sperry–Piltz Ice Accumulation (SPIA) Index uses ice accumulation, wind speeds, and temperatures to predict the impact of winter storms on public utilities (particularly power lines). The algorithm appears to be protected by copyright, which is disappointing, since it limits the ability of the scientific community to evaluate the methodology.

Communicating impact is one of the major challenges in forecasting. Even when the forecast is technically precise, the general public often doesn’t know what to do with the information. Widespread use of the SPIA Index can help people and utility crews prepare. Unfortunately, the closed nature of the index may limit its adoption.