Firefighters aided by rain have made progress fighting a massive blaze that swept through the California desert into Nevada and is threatening the region’s famous spiky Joshua trees. Fire officials say a brief, heavy downpour Tuesday afternoon helped limit the spread of the York Fire. As of Thursday morning, it was 64% contained and has burned over 94,000 acres after roaring through California’s massive Mojave National Preserve and crossing into Nevada. It’s California’s largest fire this year. However, some Joshua trees have burned. Experts say the trees — which grow only in the Mojave Desert — are unlikely to regrow if they are scorched. Firefighters are working to contain the fire without disrupting the fragile ecosystem.