Twenty-three of the 25 fires so far this year were ignited by human activity. While this year’s heavy snowpack and cold spring pushed back the start to fire season in many parts of the state, climate change is generally causing an earlier snowmelt, said climatologist Rick Thoman.

There were 4,500 lightning strikes in Alaska Tuesday — the latest in a run of days with thousands of ground strikes. There were also another 13 new, primarily lightning sparked wildfires in the state Tuesday, mostly in the Interior. The lightning storms have coincided with very dry conditions.