As we have done in previous years SWOA will keep you informed about our best estimates for potential flooding as the snowpack melts. Reviewing Provincial reports the current estimate for the expected total volume of runoff in the basin is approximately 20% above normal. This does not mean that there will be flooding or extreme high water levels in the lakes this summer as spring weather is a critical factor determining the rate that snow melts. However, it does mean that we should be monitoring these levels closely over the remainder of the winter and spring as they are of concern. We will have to wait until we have the data at the end of March and particularly at the end of April to determine if further concern is warranted.
For a more detailed description of what data was used for this please continue to read more
The Province of BC releases a report on snowpack and water supply levels for the months of January to June each year. The current report summarizes conditions at the end of February 2020. The following paragraph is the Executive Summary from that report:
“Mixed weather through February has led to on-going development of the province’s snowpack. The provincial average of snow measurements is 111% of normal, a slight increase from 110% of normal on February 1st, 2020. The snow basin index for the Fraser River is 117%, with high snow pack levels in it’s major tributaries. Seasonal flood risk is elevated in many regions, including the Upper Fraser West, Upper Fraser East, North Thompson, South Thompson, West Kootenay, Boundary, Central Coast and Skagit. Typically, 80% of the annual snow accumulation has occurred by March 1st, with another 48 weeks of snow accumulation still to come. While changes to the overall provincial seasonal flood risk are possible over the next few months (either increases or decreases), current trends in snowpack are likely to persist. Snow pack is one element of seasonal flood risk in BC, however snowpack alone does not predict whether flooding will occur; spring weather is a critical factor determining the rate that snow melts, while extreme rainfall can also cause spring flooding independent of snow conditions.”
For the Shuswap Drainage, the Snow water equivalent (SWE) at the recording stations ranged from 117% to 156% of normal, averaging 135%, down from 142% from the February report. The overall This is mainly due to lower snow accumulations over the last half of February. The estimated Basin snow water index is 127% of normal, down a few percent from the previous estimate.