The devastating Yarnell Hill, Arizona widfire continued to grow overnight as it spread near Peeples Valley.

The deadly Yarnell Hill fire started on Friday after lightning struck the area. The fire spread rapidly, devouring over 6,000 acres by Sunday. With temperatures soaring over 100 degrees in the area, the low humidity and windy conditions contributed to the rapid spread of the fire.

Nineteen elite firefighters tragically died while battling the blaze on Sunday.

The young fire crew was part of a twenty member 'hot shot' team from Prescott. All but one perished in the fire, becoming the single deadliest incident for firefighters since the terrorist attacks on September 11, 2001.

The crew reportedly deployed emergency fire shelters to try to protect themselves from the flames.

'Hot shot' firefighters are elite firefighters that are highly trained to hike for miles into the wilderness with chain saws and backpacks filled with heavy gear to build lines of protection between the blaze and people by clearing away brushes, trees, and more.

The team tragically perished when they were overtaken by the blaze, which moved very fast due to the hot winds.

Prescott Fire Chief San Fraijo spoke at a news conference Sunday: "We grieve for the family. We grieve for the department. We grieve for the city. We're devastated. We just lost 19 of the finest people you'll ever meet."

He continued: "By the time they got there, it was moving very quickly." He explained the emergency shelters that the crew was forced to deploy. "One of the last fail safe methods that a firefighter can do under those conditions is literally to dig as much as they can down and cover themselves with a protective - kinda looks like a foil type - fire-resistant material - with the desire, the hope at least, is that the fire will burn over the top of them and they can survive it. Under certain conditions there's usually only sometimes a 50 per cent chance that they survive. It's an extreme measure that's taken under the absolute worst conditions."

Some of the firefighters were found dead inside such shelters, with some found outside.

The death of the nineteen hero firefighters is the highest toll battling a wildfire in the U.S. in 80 years.

Over 250 structures have been burnt in Yarnell Hill- half of the small town's 500 structures. Hundreds have fled the area.

 See the map of Yarnell Fire as of 11:30 p.m. MDT, June 30, 2013.