The annual hydrological régime of "Jason's Creek" begins in June or early July with a 10–15 day period of flooding as a result of snowmelt, preceded by a few days of relatively low flow. In 1970, 82% of the annual snowmelt discharge left the basin between June 26 and July 15. After the flood, discharge decreases irregularly but in a roughly asymptotic fashion until the stream freezes to its bed in late August or early September. This régime is punctuated by occasional rainstorm floods. The flow of the stream varies diurnally in response to radiative and thermal inputs of energy to the basin snowpack, the lag time for these inputs being 5 h. The response of the basin to an input of rainfall is rapid and the duration of direct storm runoff short. Sparseness of vegetation and shallowness of the active layer above the permafrost are important properties of the drainage basin.