An intense and expanding heatwave is baking the South and Southwest, pushing the mercury to record-challenging levels in areas notorious for their searing summer temperatures. The stifling heat is creating an additional public health challenge in a region where coronavirus cases are also spiking. On Monday, heat warnings and advisories were in effect for at least 11 states from Southern California to the Florida Panhandle.

These include all of Louisiana, nearly the entire state of Texas and a portion of Arizona. Each of these states have seen dramatic surges in coronavirus cases in recent weeks, and the heat is complicating the effort to contain the illness by making drive-through testing centers less feasible and challenging cities’ heatwave response plans that rely in part on indoor cooling centers, where the virus could spread.

In addition to prolonged elevated temperatures, the heat is likely to contribute to increased drying of vegetation in California and other fire-prone states.