"That is is an agreement between all 50 states that if there's a need in a state impacted by a major disaster, we'll do all we can to get resources to an impacted area to help them out," said Rob Feeley, spokesman for Homeland Security.
For example, as first responders already on the scene of devastation in Oklahoma become exhausted, the call might go out for fresh search and rescue teams or additional people to staff shelters.
Should the call come, the bureau's emergency operations center would be activated to gather resources.
It wouldn't come as a surprise if Oklahoma were to ask Idaho for help.
The center has been activated before to help with fires in California and hurricanes and tornadoes in Texas and Louisiana.
Oklahoma might look first to its neighbors but with widespread storms in the forecast, those neighbors might just need help themselves.
And Idaho is ready and willing.