Duane McKay, Saskatchewan's commissioner of emergency management, said that power was out in a wide swath from Lloydminster on the Alberta-Saskatchewan boundary, east to Prince Albert and stretching north. That also included North Battleford and Meadow Lake.
McKay said the storm Monday evening downed transmission lines and towers.
"When those go down, that's significant reconstruction time to take place," said McKay.
McKay could not say how many people were without power, but he noted there are about 40,000 people in the Prince Albert area and another 15,000 in North Battleford.
SaskPower has called in crews from British Columbia to help. It said it could be 24 to 48 hours before power is restored in Prince Albert and there could be rotating outages. The Crown utility said it would six to eight hours before power is restored to Meadow Lake and North Battleford.
One of those lines in the Meadow Lake area was suspended from steel towers, said SaskPower vice-president of transmission and distribution Mike Marsh.
"To have 10 kilometres of line pushed down on its side just indicates tremendous force."
Marsh said most of the affected lines are also in rugged terrain, making repairs more of a challenge.
"(The storm) dumped an awful lot of rain," he said.
"In some cases the affected areas have had three to four inches of rain. It's extremely muddy and very difficult terrain, so getting men and equipment into that area is very, very difficult."
McKay said some homes in the storm's path were damaged, but there are no reports of serious injuries.
No tornadoes were spotted, although winds stronger than 100 kilometres an hour were recorded. McKay speculated that might indicate a plow wind.
"Some reports said that the winds came up very rapidly — calm one minute and then racing through structures immediately after that," he said.
"We don't have a definition yet, but it was significant."
The storm forced a dozen people from an apartment block in Prince Albert, where grape-sized hail and a torrential downpour caused a severe leak in the building's roof.
"I woke up and (was) getting drenched with water so I moved my bed ... then I heard a collapse in the next room and I guess the ceiling caved in," said resident Jason Henderson.
Emergency crews across Prince Albert were kept busy responding to accidents, ambulance calls and false alarms as streets flooded and traffic lights went out. Classes and buses in all school divisions were cancelled Tuesday.
The city was urging residents not to shower or flush toilets to conserve water.
The water treatment plant was without power and officials said there was a risk of backups.
In North Battleford, hail the size of baseballs driven by a powerful wind knocked out power, snapped trees and flooded sidewalks.
Saskatoon's public schools cancelled all school excursions because of the threat of severe weather.
And it didn't look like southern Saskatchewan would escape unscathed either.
Environment Canada issued severe thunderstorm watches and warnings, as well as tornado watches, for many parts of southern Saskatchewan on Tuesday.
Around supper time Tuesday, the agency issued a tornado warning for the Moose Jaw area, saying one had been spotted south of Mortlach. However, an hour later, Environment Canada said the storm that produced the tornado had weakened. There were no reports of injuries or damage.
— by Jennifer Graham in Regina with files from CKBI, CJWW, CJME