Evolution of subglacial water pressure along a glacier's length

  • Harper J
  • Humphrey N
  • Pfeffer W
 et al. 
  • 25


    Mendeley users who have this article in their library.
  • 25


    Citations of this article.


Observations from along the length of Bench Glacier, Alaska, USA, show that the subglacial water-pressure field undergoes a multiphase transition from a winter mode to a summer mode. Data were collected at the glacier surface, the outlet stream, and in a network of 47 boreholes spanning the length of the 7 km long glacier. The winter pressure field was near overburden, with low-magnitude (centimeter to meter scale) and long-period (days to weeks) variations. During a spring speed-up event, boreholes showed synchronous variations and a slight pressure drop from prior winter values. Diurnal pressure variations followed the speed-up, with their onset associated with a glacier-wide pressure drop and flood at the terminus stream. Diurnal variations with swings of up to 80% of overburden pressure were typical of mid-summer. Several characteristics of our observations contradict common conceptions about the seasonal development of the subglacial drainage system and the linkages between subglacial hydrology and basal sliding: (1) increased water pressure did not accompany high sliding rates; (2) the drainage system showed activity characteristic of the spring season long before abundant water was available on the glacier surface; (3) the onset of both spring activity and diurnal variations of the drainage system did not show a spatial progression along the length of the glacier.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Joel T. Harper

  • Neil F. Humphrey

  • W. Tad Pfeffer

  • Tyler Fudge

  • Shad O'Neel

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free