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Wildfire wildcard: How weather can help trigger an explosive fire

This week’s loss of 19 elite firefighters battling Arizona’s Yarnell Hill wildfire raises questions about how scorching temperatures and low humidity may contribute to explosive fires and unanticipated safety hazards. Here’s what researchers have learned.

Arizona illegal immigration law gets final go-ahead from court

Arizona’s illegal immigration law directs police to check the status of individuals during a legal stop or detention. It’s the latest chapter in the battle between the state and the Obama administration over which level of government has authority regarding immigration policy.