Mountains that normally see their peak snowpack in March are brown this year, thanks to a spring heat dome that baked the western U.S. for much of the second half of March. That’s raising alarm bells for the fire season, which is already ramping up. John Abatzoglu, a professor of climatology at the University of California Merced, said everything is “lining up for a potentially nasty fire season across the west… the warning signs are flashing.” The heat wave eased over the weekend after a sustained run of temperatures 11 to 17 C above normal — with highs in the 30s and 40s in some states. This would be “virtually impossible” without climate change caused by human CO2 pollution, mainly from fossil fuels. Early snow-melt has been linked to a longer fire season, as it dries out the landscape and provides more time and opportunity for fires to ignite and spread