Snowpack can and probably will continue to accumulate in the Boise mountains but it’s time for a snapshot where things stand for the 2012 conditions. We have lots of water, both in the reservoir at Anderson Dam and in the mountains above. We will start with the mountains:
The 2012 snow pack is the green line and the three previous years are the other colors. At this point 2012 is behind the 2011 and 2009 conditions and ahead of 2010.
As important as snow depth is the water content and here is a chart for the same four years:
And in this situation the water content of the snow at Trinity Mountain is the second best of the past four years. Remember, 2011 was well above average. Both Trinity Mountain and the Boise Basin are at 96 percent of average.
So the snow level is just about average. The water in Anderson Ranch Reservoir is well above average. Check out how much higher the blue line in the graph below is over the red line, which is the average.
Last year was above average too, and that line is shown in green. Increased flow releases from Anderson Ranch started in March and then were enhanced mid month until they got to 1,600 cfs. More water leaving Anderson Ranch Reservoir has helped keep the blue line flat or slightly declining. Water managers will want to free up space to capture the melting snows in May and June.
So this leaves us with the current flow chart above showing the river at 1,600 cfs since mid March. We are probably again headed for high flows before opening weekend around Memorial Day. Getting to 4,000 cfs may not be necessary if the snow melts slowly. But there is little doubt that flows well over 2,000 to 2,500 cfs will be what we see through June. In fact, that green line showing the 2011 flows is probably a pretty good guide.