An Objective Thunderstorm Potential and Severity Index for Utilities

Damage from strong to severe thunderstorms is a major risk to power reliability, resulting in millions of customer-hours of outages annually, and requiring escalated response by utility companies responsible for repair of the damage. Foreknowledge of the potential for damaging thunderstorms on a given day is critical for utilities to do appropriate planning and staffing of crew levels which may be necessary for power restoration.

However, thunderstorm days are obviously not created equal, especially when it comes to outage potential. A day with an 80% chance of weaker thunderstorms which have limited outage producing potential can have a much lower impact on SAIDI than a day with a 30% chance of storms, but where any storms which do develop have a much greater likelihood of becoming outage producing, with gusty winds and lightning being the main contributors to outages.

There are a myriad of convective potential parameters available to use in determining the outage producing potential of storms, but no single parameter can give you a complete idea of the potential of outage-producing thunderstorms throughout the year, as different parameters are often the driving factor at different times of the year. However, by creating a blended approach which utilizes several parameters, utilities can get an indexed number which they can then relate to each day’s threat. This can give utilities an objective guide to use, in conjunction with the overall risk of thunderstorms, to determine the total outage risk across their service territory for any given day, and assist them in knowing when to hold crews for outage restoration and more quickly recover from thunderstorm events.