Jackie Hai/KJZZ

The sun.

For more than 20 years, the Border Patrol’s Tucson Sector has conducted annual warnings and ad campaigns stressing that crossing through the desert in the summer could be fatal.

Agents ran a simulation of what migrants could face as reporters clambered into the back of a nondescript moving truck.

"Come into this truck and experience what migrants might feel or might experience," said spokesperson Daniel Hernandez.

Less migrants have been found dead in Arizona’s desert the last few years, in part because illegal immigration from Mexico has been dropping. But this year, record numbers of asylum seekers have been escorted up to remote areas of the Mexican border and dropped off and then taken into custody by American federal agents.

"The ongoing practice of smugglers dropping off large caravans, large groups of aliens in the desert in desolate areas is something that poses a tremendous threat," said Tuscon sector Chief Raoy Villareal.

Rescue beacons have been activated by migrants seeking help in the desert about 70 times this year. But large groups, such as a recent 400 who surrendered to agents in Western Arizona recently, could wait for hours before federal agents are able to reach them. 

The temperatures start crawling into the 90s in Ajo next week.