Mild weather delayed the opening of Manitoba's winter road system and is now causing them to close early. (CBC)

Mild weather sweeping Manitoba has forced more than half of the province's ice roads to close after less than a month, cutting off the winter lifelines for dozens of northern reserves.

Aboriginal chiefs are asking Ottawa for funding to fly supplies into at least 20 communities that need everything from building materials and bulky groceries to gasoline.

Grand Chief David Harper, who represents Manitoba's northern First Nations, said only about one-quarter of the orders for such goods placed by his communities have been filled since the roads opened Feb. 12.

"A lot of things have not made it up the winter roads," Harper said. "We're just praying for cold weather.

"According to the elders, we'll still get some more cold weather. But the ice is deteriorating from the bottom so we have to deal with the issue of safety."

'We're just praying for cold weather.'—Grand Chief David Harper

Without an adequate buildup of ice and snow over the winter, northern communities lose any chance of bringing in supplies at a reasonable cost. Otherwise, goods have to be flown in at great expense.

Warm weather early in the season already delayed construction of the roads, which span 2,200 kilometres and connect the northern and southern parts of the province. Even roads that opened last month had weight restrictions and the province warned users they could be closed for repairs at short notice.

The problem has been compounded by bureaucratic delays at Indian and Northern Affairs Canada, Harper said. Some shipments didn't get federal approval until it was too late to truck them along the ice roads, he said.

Fuel supplies running low

Harper said fuel supplies are running low and building materials needed for construction and renovations haven't arrived.

Aboriginal chiefs are meeting with representatives from Indian Affairs over the next few days to discuss how to make up for the short ice-roads season. Supplies will need to be flown in, but Harper said reserves can't afford to do that without federal help.

It's not clear how much it will cost to airlift the supplies, Harper said.

"Indian Affairs doesn't provide for that," Harper said. "We're asking for meetings right away."

No choice but to close roads

Larry Halayko, director of contract services with Manitoba Infrastructure and Transportation, couldn't estimate how much traffic had been able to use the roads in the short time they were open.

But he said the province had little choice but to shut them down. Recent above-average temperatures, combined with a relative lack of snow, are to blame, Halayko said.

"When you're constructing a winter road, you pack the snow to allow the frost to penetrate the ground. It also reflects the sunlight quite nicely. When that starts wearing away, then you get to the darker ground and the road won't hold up."

Environmentalists have been warning climate change is putting these traditional winter routes in jeopardy. They say mild winters, with increasing average temperatures, are becoming more common in Manitoba.

The Manitoba Eco Network says warmer weather not only makes ice roads less safe for drivers, but threatens to further isolate First Nations. Roads that had previously been open for 60 days during the winter are now only usable for about 20, it says.