Melting snow slides off rooftop solar panels and damages cars

What happened

Overnight on Sunday 21 February into Monday 22 February 2021, a large sheet of melting snow and ice slid off the rooftop solar panels of a home in Hoffman Estates, Illinois. The snow fell onto two parked cars. One windscreen was smashed and the roof of the other was caved in. The homeowner reported a loud rumbling noise and said nobody was hurt. The same warm spell caused other roof problems in the Chicago area that day, including a roof collapse on the West Side and a gas meter regulator broken by falling ice in River Forest. Fire services advised residents not to clear roofs themselves and to use a roof rake from the ground or hire a professional.

Contributing factors

Snow and ice had built up over February 2021 and began to melt above freezing. A solar installer commenting in the report said snow and ice tend to slide off smooth solar panels and that guards can reduce the risk. The installer also said snow can fall from any roof, with or without panels. The source does not state that the panels or their mounting were faulty.

Lessons learned

1. Where snow loads are high, assess whether a roof with solar panels needs snow guards or other shedding controls to stop large sheets sliding off onto people, vehicles or walkways.
2. Advise customers that parked cars and paths below a panelled roof can be at risk during a thaw, and suggest they move vehicles away from the eaves.
3. Do not clear snow from roofs with solar panels by standing on the roof; use a roof rake from the ground or a professional service.

More lessons on weather and external hazards, outages, backup supply and restoration, from every incident on the register.

Source

cbsnews.com