The Highland fire in Riverside County exploded to over 2,487 acres on Tuesday, doubling in size since the previous day and putting some 4,000 people under mandatory evacuation orders. The blaze is 10% contained. Officials said Tropical Storm Hilary could partly be to blame for the fire, noting that the heavy rainfall encouraged new grass growth that has since dried up and started feeding the flames. That “green-up” effect, paired with this week’s Santa Ana winds, have turned an otherwise manageable fire into a behemoth.