Snowpack triggers no alarms

Hydrologist says no fear of flooding or drought over snowpack reading of 81% of normal for Okanagan hills

Hydrologist Jonathan Boyd calls the Okanagan’s latest snowpack level “refreshing” and “ideal.”

“A reading of 81 per cent of normal is definitely currently not a cause for concern, neither for flooding nor for drought,” said Boyd, who works out of B.C.’s River Forecast Centre in Victoria.

Of course, a lot can change between now and June, the month when we usually know for sure if we’re going to have an excess of water, a dearth or just the right amount.

Boyd describes snowpack in the mountains surrounding the Okanagan Valley as our bank account of water for the year.

The white stuff accumulates at higher elevations in the winter and melts in the spring to feed all the streams and creeks that fill Okanagan Lake.

Mission Creek is annually responsible for about 30 per cent of the inflow to Okanagan Lake.

That means the snowpack readings taken at the Mission Creek automated snow weather station are telling.

The March 1 reading there was 80 per cent of normal, in keeping with the average taken at 20 other Okanagan stations.

The Mission Creek station is at an elevation of 1,794 metres, much higher than the City of Kelowna’s elevation of 344 metres.

The snow depth at that lofty elevation is 125 centimetres, or 1.25 metres.

When it melts, it will translate into a snow water equivalent of 31.2 centimetres, or a little under a third of a metre.

There are wildcards when it comes time for the snow to melt and water to flow into streams, creeks and eventually Okanagan Lake.

If the spring weather is abnormally warm, the snow melts more quickly, clogging creeks and potentially causing flooding.

Heavy rain as the snow is melting can also produce volumes of water that will swell creeks and lead to possible flooding.

All that water eventually makes it into Okanagan Lake, where it can flood.

On March 1, 2017, the Okanagan snowpack was 86 per cent, which wasn’t particularly a cause for alarm.

However, record rain in the spring as the snow started to melt caused record flooding along the creeks and in Okanagan Lake.

The same time in 2018, the snowpack of 141 per cent posed an extreme flood risk and, indeed, there was creek and lake flooding.

But, it wasn’t as bad as in 2017 because there was time for officials to take down the level of Okanagan Lake to handle the excess of water.

Boyd said 2017 and 2018 were unique years, back to back.

“There’s no indication 2019 will be similar,” he said. “No one is raising an alarm.”