One fire began late last night on Provo's 'Y' Mountain. Crews believe fireworks started the 10-acre blaze around 1:30 a.m., and investigators have a 35-year-old man and woman, 23, in custody. Investigators suspect the two -- both of whom are listed in Brigham Young University's student directory -- are responsible for starting the blaze with fireworks.

The flames burnt grass, sagebrush and oak brush, but are under control. Fire crews will not declare the fire contained until tomorrow morning, since today's heat could flare up remaining hot spots. The area's trail system created natural fire breaks that helped contain the fire quickly, plus the fire began late at night -- a relatively cool time.

A spokeswoman with the National Forest Service stressed that if a person starts a wildfire, he or she can be held responsible for all costs associated with fighting it. So far the 'Y' Mountain fire has racked up a $30,000 bill, including costs for two choppers and a team of 50 firefighters.

Another fire of undetermined origin completely destroyed the abandoned Bridal Veil Falls Restaurant late last night. Investigators will look into what triggered that fire later today, but it also is believed human-caused.

Clark described the restaurant as an old, deteriorating structure at the mountaintop where a tram used to run. Kids often hike up to the restaurant, and Clark said there have been issues with vandalism since the building shut down in early 1997 after an avalanche swept through the area.

That fire was contained to the restaurant and did not spread to any vegetation, Clark said.

And a third fire, in Diamond Fork's Monks Hollow area has burned about 3-to-5 acres just off Spanish Fork Canyon.

Investigators also have not determined the cause of that blaze, but Clark said there is a five-person squad battling the fire.

"That one is looking really good," Clark said.

Temperatures are expected to reach 102 degrees later this afternoon.