wildfires August 27, 2020 10:37 am The Cloud That Tells Us a Wildfire Is Growing Explosively Chances are you’ve seen a pyrocumulus cloud if you live in an area prone to wildfires. But how does it form, and what can it tell us about a fire? NBC Bay Area’s Rob Mayeda explains. US & World Videos 1:36 Arizona Senate repeals 1864 abortion ban 1:40 Democrats say Big Oil misled public for decades about climate change 5:44 May Day demonstrations, Gaza war protests continue across Bay Area 3:27 May Day demonstrations planned, Gaza war protests continue across Bay Area 2:27 Junk fee law bans restaurant surcharges