Firefighters in the Alberni Valley spent their day Monday mopping up a wildfire that rapidly spread to 15 hectares over the weekend.

Even more alarming, fire information officers say, is that it was human-caused.

The wildfire at Mount Arrowsmith sparked on Saturday, growing quickly to 15 hectares by Sunday morning and becoming the island’s largest wildfire of the season.

“It was pretty big for an island fire for a coastal rainforest, but the challenge here is how steep it is,” said firefighter Shawn McKay. “Then typically with logging debris, it’s a fairly labour intensive fire.”

Dozens of personnel attacked the blaze throughout the weekend and were able to fully contain it as of Monday morning – and a large swath of charred mountainside was all that remained Monday afternoon.

arrowsmith fire

McKay said that conditions were favourable for burning following a weekend heat wave that put two-thirds of Vancouver Island under a high fire danger rating.

“As soon as the value of the temperature is higher than the value of the humidity, that’s known as crossover and that’s when you get really aggressive fire behaviour, and that’s what was happening here,” he said.

Despite a wetter-than-usual spring on much of the island, fire officials say conditions might actually be drier than the public thinks.

“Complacency is always a problem that we have when we have a really wet period of time, but we’ve had some very hot temperatures into the mid-30s, maybe higher in the Port Alberni Valley,” said information officer Marg Drysdale, of the Coastal Fire Centre.

The exact cause of the fire is under investigation but officials have already confirmed it’s human-caused.

Since April 1, there have been 21 fires within the Coastal Fire Centre and all have been caused by people.

“It’s always a concern when it’s human-caused fires. They’re always preventable. So people just have to think ahead what they’re doing,” said Drysdale.

With cooler temperatures forecast for the remainder of the week the fire centre says campfires will likely be allowed come Canada Day long weekend, but warn that could change with more human-sparked fires.