Some flooding risk indicated by snow levels

Snow measurements show there's more than normal in the Okanagan hills, which could mean high water levels as it melts.

Despite lower amounts of winter snow on the west side of the lake than on the east side, overall there is more snow in the hills around the Okanagan than normal for this time of year, so there’s a moderate risk of some flooding this spring.

However, the deeper snow bodes well for water managers concerned about storing enough water in reservoirs for use by valley residents during the dry summer months.

David Campbell, section head for the province’s River Forecast Centre, says typically by the beginning of March, 80 per cent of the winter season’s accumulation of snow has already fallen, so there’s a good indication of the amount of inflow Okanagan Lake will receive during snowmelt.

And, it’s the largest water storage reservoir in the valley.

He doesn’t anticipate snow at medium to high elevations around the valley will begin to melt for another few weeks, but he says there is 15 per cent more snow than normal, on average around the Okanagan.

While the automatic snow pillow measuring station in the Brenda Mine area on the west side of the lake reports less than normal (72 per cent of normal) and less snow than last year at this time, the nearby, but higher-elevation Whiterocks Mountain is at 98 per cent of normal.

Across the lake, the Mission Creek station reports more than average, or 13 per cent more than normal, and it provides the largest single inflow of meltwater in the valley.

Campbell noted that there have also been a couple of storms since the March 1 measurement.

Ken Cunningham, regional manager for resource management for the natural resource operations ministry, said there seems to have been a rainshadow effect on the valley’s western slopes the past couple of years, yet those reservoirs have filled without a problem.

Last year, a delayed snow melt, and additional late-season snow accumulations at higher elevations, combined with steady rain in the valley, “created all sorts of problems,” he commented.

However, without the other factors there’s no reason to forecast flooding again this year, he feels.

Even if there is adequate snowpack accumulations over the winter months, and reservoirs fill with stored water for irrigation and domestic use around the valley, he warns there can still be a dry, hot summer and it’s all gone before summer is finished.

So, it’s important that people conserve water throughout the year, in order that there’s enough left to carry us through the dry season when water use is also at its highest, he added.

The level of Okanagan Lake is close to the target for this time of year, and more water is being released downstream than last year at this time, he said, to make room for a higher snowpack.

The RFC reports that there is some indication of an increased likelihood of wetter and cooler weather over the remainder of the snow accumulation season, with a moderate increase in seasonal flood risk in the Okanagan.



Kelowna Capital News