UPDATE (10:43 a.m.)

Power has been restored to all but three customers, who are located in the Bar Nunn area. Those continuing outages are estimated to be resolved by 12:30 p.m. and 1 p.m., respectively.

UPDATE (9:49 a.m.)

Rocky Mountain Power now reports 161 customers remain without power in the Casper area. 

The largest outage, reported just before 4 a.m., is still estimated to be resolved by 10 a.m. The cause remains under investigation.

Two smaller outages, near Bar Nunn and Vista West, respectively, each affect one customer. The Bar Nunn outage is expected to be resolved by 11:30 a.m., while the outage near Vista West has an estimated restoration time of 12 p.m.

UPDATE (9:19 a.m.)

The number of customers affected by Thursday's power outage northwest of Casper has fallen to 558, according to Rocky Mountain Power.

The company still estimates power will be restored to all customers before 10 a.m.

UPDATE (7:21 a.m.)

Rocky Mountain Power crews continue to make progress despite brutally cold conditions, with the number of customers affected by the power outage now reduced to 635. 

The cause of the outage remains under investigation. 

UPDATE (6:43 a.m.)

Rocky Mountain Power now reports the number of customers affected by the power outage has been reduced to 1,592. The estimated time for power to be fully restored is 10 a.m.

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Some 1,732 Rocky Mountain Power customers were without power northwest of Casper Thursday morning as frigid temperatures were only made worse by wind chill values.

The outage -- reported in the area of the Casper/Natrona County International Airport, Bar Nunn and Homa Hills -- was first reported just before 4 a.m. The power company says crews have arrived and the cause of the outage is under investigation.

The company estimates power should be restored by 10 a.m.

Meanwhile, the National Weather Service reported a temperature of -20F at the airport, while wind chill values pushed that figure to -40F as of 6:20 a.m.

This story will be updated as more information is made available.