An improvised nuclear device is set to go off somewhere in the metropolitan Phoenix area this week. Don’t forget there’s going to be a major flood too.

Not really, but thousands of people from numerous agencies across the state are going to pretend Phoenix has been nuked and flooded to test their coordinated disaster response in the event the unthinkable ever did happen.

It’s called Vigilant Guard Arizona, and it’s the largest such exercise ever to be held in Arizona with 250 agencies and thousands of people participating, including the National Guard and emergency responders statewide.

The exercise is scheduled to run from Thursday through Sunday, Nov. 3 through 6. The Yavapai County Health Department, the American Red Cross and the Camp Verde Fire District will be taking part in the event Saturday, Nov. 5, said Brian Supalla with Yavapai County Health Services.

While the nuclear “event” takes place in the Valley of the Sun, the entire state would be affected by a devastating nuclear explosion in the capital.

Local agencies will be using Camp Verde High School as a staging center to treat evacuees from down south and serve as a decontamination center for those who might have been exposed to radiation.

“We’ll be working with the HAZMAT [hazardous materials response team] to scan people,” Supalla said. “We’ll get them decontaminated and processed. Exposure to radiation could cause effects that show up years or decades later.”

The exercise will involve several volunteers who have agreed to role play as Phoenix residents fleeing ground zero.

Other local agencies are participating, including Verde Valley Medical Center, where large tents will be set up to deal with the influx of mock patients, Supalla said. Residents shouldn’t be alarmed.

Barbara Rice, CVFD fire marshal, said exercises like this are crucial for preparation just in case.

“Especially after 9/11, I think there are a few targets in Arizona that could be targeted,” Rice said. “There’s Phoenix and there’s also the Palo Verde nuclear plant.”

Rice said in the event of such a disaster, most likely every emergency agency in the state would have to respond in some way or another.

On his blog, Arizona Department of Health Services Director Will Humble noted the exercise and stated his agency would be fully activated. He added everyone should have some sort of plan in place in case of an emergency.

“As the recent wildfires have shown us, it is important to have a personal/family evacuation plan and a separate shelter-in-place plan,” Humble wrote. “In some cases, it is best to hunker down at home and wait for the danger to pass. Shelter-in-place planning will require you to stockpile key resources such as food, water, medicine, flashlights, radio, etc. Evacuation planning is a bit different. In this case you will need to have additional items ready to go such as identification, cash, clothing and mess kits.”

After the Camp Verde event ends Saturday afternoon, Supalla said the on-site participants will review their performance. That will be followed up by a statewide discussion where every participating agency will evaluate the state’s response when it comes to handling a crisis of epic proportions.