Alarmingly low snow levels in the Rocky Mountains will cut water supplies to Canada’s Prairies and could help trigger a river drought in the important farming region, a leading expert said May 27.
The predictions by University of Saskatchewan hydrologist John Pomeroy were particularly gloomy, given that 2009-10 was a record dry winter for the western Prairies.
“It’s clear that we have serious problems and will have more serious problems in the future,” Pomeroy said in a presentation at Parliament in Ottawa.
After severe drought in parts of Saskatchewan and Alberta last year, many farms have seen too much moisture this spring, setting back planting in both provinces.
But parts of the region depend heavily on rivers that extend across the Prairies, fed by snow, rain, glaciers and lakes in the mountains.
“There is a severe drought in the western mountains and if it carries on it will be a river drought extending across the Prairies,” said Pomeroy, a specialist in both Prairie droughts and predicting snow changes in the Rockies.
The scientist said he had visited a research site some 900 metres (2,950 feet) up a mountain in the Alberta Rockies recently to check for snow.
“What horrified me when I struck the tree line was that I could see the trees. Normally they’re buried,” he said.
“They were brown and red because they’d been killed off by the dry chinook winds over the winter … the snowpacks are really low this year, the lowest I’ve ever seen.”
Separately, the U. S. space agency NASA said the North American snow cover this April had retreated to its smallest extent for the month since records began in 1967.
Pomeroy said models show that a temperature increase of 3 C in the mountains would be “a tipping point – we have the collapse of the alpine snowpack.”
Pomeroy said prairie farmers have already begun to adapt to the drier conditions, in part by using more efficient methods and by growing pulse crops, such as beans and peas, which require less water.
“One of the triumphs we had is that (although) this last drought meteorologically was very very severe, we did not have a collapse of the Prairies’ economy,” he said.
Other simulations show that, by 2080, global warming means the amount of spring run-off available in the southern Prairies would be 37 per cent less than now, Pomeroy added.