HUNTSVILLE, ONT. -- The warm weather mixed with dry conditions are a recipe for disaster, pushing fire officials to set the fire danger rating to high this week.

Huntsville fire officials determined two grass fires earlier this week in the Lake of Bays were caused by natural causes, prompting a warning about the dry conditions ahead of the Victoria Day long weekend.

Huntsville/Lake of Bays fire chief Rob Collins said the first fire that sparked on Monday was quickly extinguished, but the second had crews battling hot spots and hot weather conditions.

"The fire has spread to somewhere between 10 to 15 acres, so you can imagine a lot of work actually going into making sure all of those hot spots are out. It's heavy work. It was a warm day," he said.

"All it takes is one afternoon with a high wind and low humidity - it's very easy to start a fire," said Huntsville fire prevention officer Mike Vadlja.

Vadlja added that wooded areas with lots of sticks and leaves on the ground would need about 10 to 15 millimetres of rain to prevent a fire from sparking.

"The longer we go without rain, the dryness will move further down into that duff layer, and things will get a little more dangerous," he explained.

Fire officials expect campers and cottagers to visit the area and caution that even though backyard fires are permitted in Huntsville, the fire danger rating will remain high throughout the long weekend.

"All we ask is that people if they're going to have a campfire or anything, is just making sure that they do put them out," Vadlja said.

Fire officials warn that if conditions worsen, they won't hesitate to elevate the rating to extreme, prohibiting any open burning, including campfires.