Scientific adventurer Peter V. Hobbs, who flew over Mount St. Helens within hours of the 1980 explosion and ventured into thunderstorms and cyclones trying to understand how rain and snow form, died July 25. He was 69.

The renowned University of Washington researcher operated an airborne laboratory for 30 years.

Born and educated in England, Hobbs said he moved to Seattle because it is “the cloud capital of the world.” He acquired his first research plane in 1969 and eventually flew into clouds over the Cascades, volcanic dust in Alaska, oil smoke in Kuwait, and anything else he and his colleagues wanted to study.

Hobbs’s efforts transformed a fledgling program into one of the leading atmospheric science groups worldwide.

His discoveries about ice crystals in clouds are a cornerstone of modern weather-prediction models. He also studied the role of aerosol pollutants in dampening the effects of global warming.

Just last year, he reported the largest raindrops on record: nearly grape-size droplets over Brazil and the Marshall Islands.

He was co-author of a popular atmospheric science textbook for graduate students, “Basic Physical Chemistry for the Atmospheric Sciences.”