Climate Central: On Monday night, Jim Wallmann drove north from broiling Phoenix toward a bustling command post for the Yarnell Hill fire near Prescott, Ariz. The blaze had killed 19 of the 20-member crew of elite "Hotshots" a day earlier in the worst loss of firefighters in a single wildfire in 80 years. With erratic weather conditions viewed as the primary suspect behind the tragedy, Wallman had been called to the blaze specifically to prevent a repeat incident by keeping firefighters informed of changing weather...