Authorities have yet to declare a cause of the fire, but weather conditions have made the situation more dangerous. Fort McMurray broke a daily record high temperature last Tuesday, hitting 90 degrees. The previous daily record high was 82 degrees, set on May 3, 1945. Fort McMurray's all-time record high for May was 94.6 degrees on May 26, 1986.

Each month this year has been drier than average in Fort McMurray, and the city was 1.09 inches below average on precipitation for the January through April time period. Fort McMurray has received just 0.04 inches of precipitation since April 15