Fishtrap Creek is a snowmelt-dominated stream. Historically, streamflow begins to increase in April and peaks in May, then gradually declines into July and August.  Between September and March, flows remain low, though occasional rain and rain-on-snow events are evident in the hydrologic record.

 

(the adjacent figure plots the mean monthly runoff, in cumecs, for a standard water year starting in October)

Peakflows in Fishtrap Creek historically have occurred between April 22 and June 02, with an average peak flow date of about May 15. The average instantaneous peak flow is about 7.4 cumecs, ranging from about 3 cumecs to just over 15 cumecs.

 

Since the fire, the peakflows tend to occur earlier, and there is some evidence that flows are being de-synchronized, since the runoff pattern for two of three years shows a distinct double peak to the hydrograph (the data from early April is missing for the 3rd year). This de-synchronization may be masking a post-fire increase in the total stream runoff...the hydrological effects of the fire are still under study.