Steve Roberts, the province's executive director of wildfire management, says humidity is so low in areas where fires are burning that there are "crossover conditions."
Roberts says in such conditions, fires become volatile, and crews are aware they may need to flee in a hurry.
He says lightning Friday night sparked close to 40 fires, bringing the provincial total to 113 on Saturday.
"This is probably as tough as a situation as we've encountered in say 10 years," Roberts told a news briefing about the Saskatchewan fire situation on Saturday.
Over 1,000 people in the areas of La Loche and La Ronge have been advised to leave their homes due to smoke from the fires, as well as smoke from other fires that has blown east from Alberta.
The heat wave has also prompted officials in Alberta and B.C., where conditions are also dry, to urge caution while in the forests to prevent sparking fires.
Alberta Health Services issued heat advisories all over the province. Residents were advised, among other things, to take breaks from the heat at pools or air-conditioned public buildings, to drink plenty of water and wear wide-brimmed hats.
In B.C., where Vancouver officials identified the locations of 250 permanent and six temporary water fountains in advance of the weekend heat, provincial staff continued to keep a close eye out for new forest fires.
Navi Saini, a fire information officer based in Kamloops, said about half of the province is rated high or extreme for fire risk.
Some of the greatest risk this weekend is on the coast, which is typically wetter than the province's interior.
"They haven't received any of that June rainfall that they normally get," explained Saini, where it was 39 C outside her air-conditioned office on Saturday.
The situation wasn't quite the same in Manitoba, however, where Environment Canada issued severe thunderstorm watches and warnings, and even a tornado warning southwest of Winnipeg on Saturday.
Reena Spearman, who works in the grocery store in the small community of Roseisle, believes a twister touched down while she was working.
It started with hail the size of pennies. Then it was the size of tennis balls. And then the wind started to blow.
"It was just a white wall of hail and leaves and branches. But it was curved and going around," said Spearman.
Cars are wrecked from the hail, she said, and farmers' fields are flat. The electricity was out for hours. But she didn't believe anyone was hurt.
Environment Canada lead meteorologist Jason Knight couldn't confirm the storm produced a tornado, but said he'd heard reports the hail was the size of softballs.