Snow pack in the Salmon River basin through most of the winter has been 110-120% of average. Based on snow pack, Salmon River level projection for the summer is average or a bit over–welcome after last summer’s low water. While the current snow pack is encouraging, it is not a guarantee. If the weather is warm and dry during the remaining winter and the spring, we could still end up with low river levels next summer–or, if wet and cool, high water in early summer with stronger late summer flows. Since the Salmon River is a free-flowing stream, snow pack and rain are very important.
The Middle Fork of the Salmon is more sensitive to river levels than the Main Salmon. The peak of snow melt, and river level, is usually in early June. In a low water year, the peak is earlier, in late May. In a high water year the peak is later, mid-June or even later. The access road to the Middle Fork becomes snow-free roughly about the time the river peaks. In a high flow, risk of accident increases on the Middle Fork. The river is cold, fast, and powerful. Probability of an accident isn’t necessarily greater in high water if a boatman knows the river well, but the consequences are more serious.
As the river drops later in the summer, it reaches a level that is impractical to get a loaded boat down the upper end of the river. By flying passengers and some supplies into a river-side airstrip about 25 miles downstream from the usual launch point, we can continue to provide trips into early fall.
We have about the same window of time each year between river levels that are a bit too high for comfort, and too low for a load on the upper end of the river. That window slides earlier in a low-water year, later in a high-water year. With the current snow pack, we expect to have typical pattern of river level–comfortable by mid to late June, run off the top until the beginning of August, then fly in during August and September.
On the Main Salmon, which carries a larger volume of water than the Middle Fork, low river level is not a serious issue. There is no problem with late summer trips. In early summer, though, just as on the Middle Fork, peak flows in early June can be high enough to increase risk. Main Salmon river level projection this year suggests comfortable levels by late June, continuing into early fall.