OSOYOOS TIMES-March 17, 2010

By Paul Everest – Osoyoos Times

The Okanagan Valley could be facing another summer of low river levels and reduced lake and groundwater storage due to below-average snowpack levels around the province.
“If you’re in the Okanagan and you need water, pray for rain,” said Bill Kuhnke, the manager of forecasting information for the B.C. Environment Ministry’s Water Stewardship Division.
Data released by the ministry on March 8 shows that snow packs in all of the province’s major river basins are below normal.
Right now, the Okanagan-Kettle basin is at 86 per cent of normal snowpack levels.
While the Okanagan basin as a whole is being referred to as “dry” in a provincial water supply and snow survey bulletin issued March 1, the Osoyoos area is faring better than other parts of the valley.
According to the bulletin, which used data from 152 snow courses and 50 snow pillows around the province, the Mount Kobau snowpack is at 119 per cent of normal, compared to 43 per cent at Vaseux Creek north of Oliver and the overall basin index of 86 per cent.
Kuhnke said even though the Mount Kobau snowpack is above normal and might benefit some nearby creeks and streams, it won’t help out any lakes or water systems in the Okanagan Valley.
The bulletin states that “a portion of the South Okanagan (approximately Penticton and south) appears to have near or above normal snow at high elevation, while the rest of the Okanagan is below normal.”
Environment Canada precipitation data collected at the Penticton Regional Airport (precipitation data for Osoyoos was not available) shows that the South Okanagan received 39 millimetres of precipitation in January and 32.2 millimetres in February.
For this month, as of March 10, the area had received 0.4 millimetres of precipitation.
The normal precipitation rates for the area based on 30-year trends for those three months are 26.8 millimetres, 22.5 millimetres and 22.3 millimetres respectively.
Low snowpack levels are being blamed on warm and dry conditions in the past two months caused by “a moderate to strong El Nino” weather pattern, the bulletin states.
Environment Canada has announced that this was the warmest and driest winter Canada has experienced since 1948.
In Osoyoos, the average temperature for January was 1.83 C, up from the normal average temperature for that month of -2.1 C.
In 2009, the average temperature for Osoyoos in January was -3.6 C.
February was also a warmer month for Osoyoos with an average temperature of 4.44 C, up from 0.82 C for February, 2009.
The normal average temperature in Osoyoos for that month is 1.1 C.
Since 80 per cent of B.C.’s mountain snowpack usually has accumulated by the beginning of March and there are only a few weeks left for more snow to accumulate, potential “water-supply challenges” are being forecast for this summer for several regions within B.C.’s Interior including the Okanagan Valley.
“At or above normal” rainfall in April, May or June could reduce the potential for a summer drought or low river flows in the basin, the bulletin states.
According to Environment Canada, the normal precipitation rate for the South Okanagan for April is 26.6 millimetres, the normal rate for May is 37.3 millimetres and the normal rate for June is 38.9 millimetres.
Last year, 7.2 millimetres of precipitation fell in the region in April, 18.6 millimetres fell in May and 28.2 millimetres fell in June.
In 2008, precipitation levels for April and May were also below the normal rate at 13.4 millimetres in April and 35.2 millimetres in May.
Rainfall in June, 2008, however, was above the normal amount at 45.4 millimetres.
Because of the current snow and weather conditions, the provincial River Forecast Centre is forecasting that water inflows to Okanagan Lake for the period of February to July will be roughly 69 per cent of normal.
Inflows to Okanagan Lake are a determining factor for whether or not a drought year will be declared for Osoyoos Lake.
Last year, the Osoyoos Lake International Board of Control, which is responsible for monitoring and controlling water levels in the lake, declared a drought year for Osoyoos Lake because of below-normal flows from Okanagan Lake and the Similkameen River and because water levels were 38 centimetres below normal in Okanagan Lake.
The board will declare whether 2010 will be a drought year for Osoyoos Lake in April.
Kuhnke said if current dry conditions continue in the Okanagan Valley, this summer’s drought situation could be worse than last year’s.
The ministry doesn’t expect spring precipitation levels to make up for the below-normal snowpack now, he said, but added that spring rains have helped in the past.
One meteorologist said, however, that there is some good news for this spring.
Ross Flock of Environment Canada said the prediction for the next few months is that the El Nino system which is affecting weather in the Pacific Northwest area of North America will weaken.
As it does, he said, precipitation and temperature patterns will return to “climatologically normal conditions.”
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