TULSA, Oklahoma - Around 38,000 customers across four counties are still without power Friday, but PSO says they hope to have all customers back on line by 5 p.m. on Monday.

Storms with 70 mph winds snapped power poles across Tulsa, Wagoner, Osage and Craig counties Thursday.  

PSO says this storm was one of the worst in its history, in terms of the number of power outages.  The utility says on Thursday at 4 p.m., PSO had more than 100,000 customers without power.

The utility says crews have been out all night.

Utility crews saw a lot of debris, downed trees and limbs across power lines, breaking many poles.  Since the damage is so widespread, the utility says some customers may have to wait until Monday before power is restored. 

PSO has set up a staging area at the Tulsa County fairgrounds and have called in about 1,200 extra workers to help in the restoration effort.

Tulsa Public Schools says there will be no summer classes Friday at two of its schools due to power outages. The district says East Central High School and Lewis and Clark Elementary School have canceled classes for Friday.  NSU says its campus in Broken Arrow and Tahlequah were also closed Friday.