The late spring in the Yukon and an above-average snowpack in some areas has created a moderate flood risk for several communities, says a government hydrologist.

Ric Janowicz said Tuesday afternoon officials are keeping an eye on Old Crow, Dawson City, nearby Rock Creek, Ross River and Upper Liard.

Conditions in the Southern Lakes district and through the upper reaches of the Yukon River watershed are not a concern at this time, he said during a 45-minute briefing for reporters.

Janowicz emphasized anything is still possible, including a slow melt that could see the snowpack and river ice leave without a peep.

Then again, when the cold snap does break, temperatures could sour overnight, rain could pour and problems could arise, he said.

That is exactly what happened to cause the record flooding last year at Upper Liard, west of Watson Lake.

Janowicz said for Old Crow, the issue is not the snowpack, which is well below average across all of northern Yukon.

Rather, it is the Bluefish River and how its flow into the Porcupine River below Old Crow can cause an ice dam that plugs the Porcupine and backs up water all the way to the community of 250. The village last experienced a major flood in 1991, Janowicz noted.

The village site, he said, is between three and four metres above the wintertime level of the river.

Janowicz said because ice formation coming from the Bluefish has crossed the entire Porcupine, and is thicker than normal, a moderate flood risk has been assigned to the community.

"But it all comes down to timing in the end,” he said.

The manager of Environment Yukon's water resources branch said the river ice at Dawson and Rock Creek is also thicker than normal because of the cold winter.

Weather records for Dawson go back 107 years, and the past winter was coldest in the last 15 years and the 30th coldest on record, Janowicz pointed out.

He said the thicker river ice, combined with the current cold snap and an above-average snowpack in the Dawson area, creates cause for some concern, particularly at Rock Creek on the banks of the Klondike River.

River ice at Rock Creek is normally the first to break up in the last week of April, followed by the break-up at Dawson in the first week of May, he said.

Janowicz said once the Yukon emerges from the unseasonably cooler temperatures – it was -22 C in Dawson Monday morning – two things can happen.

Temperatures going into late spring could climb gradually, causing the river ice to slowly lose its integrity and turn to mush with no muscle left to cause an ice jam, he explained.

Or, he added, things could heat up quickly. That would cause a quick melt and break-up while the ice is still strong, with plenty of power to cause a jam and hold back water.

"We have assigned Rock Creek a moderate flood risk,” Janowicz said. "We are not quite as concerned about Dawson.”

Dawson does have the flood dike, built in the mid-1980s, and break-up there is also influenced by the break-up of the White and Stewart rivers, where the river ice is not as thick and the snowpack is not as high, he said.

"Perhaps we could have a test of the dike but we do not expect the dike to be breached.”

The dike was constructed following the disastrous 1979 flood that cascaded into most parts of Dawson City, causing severe damage to buildings.

Janowicz said officials have assigned a moderate flood risk to Ross River as well, because it's a low lying community and the snowpack in the Ross River and Faro areas is 30 to 50 per cent above average.

"And we are concerned about some of the smaller streams in that area,” he said. "Some of the mining sites could have some issues this year.”

Janowicz said the community of Upper Liard has also been assigned a moderate risk because of its low-lying elevation, and not the accumulation of snowpack.

It is significantly lower than it was last year, when the community was hit with the perfect storm of a warm temperatures, rain, and a snowpack that was ripe for the melt when everything came together, he said.

Following the Upper Liard flood disaster, the Yukon government bought out the 11 homes and properties in the lowest-lying area next to the Liard River.

Janowicz said the Yukon as a whole is about 10 days behind in temperature, and it's not expected to get back to normal for about another 10 days.

While the melt in the valley bottoms and in everybody's yard has begun, the snowpack has not yet started to melt, he said.