The impacts of the 1998 El Niño weather pattern, followed by its cold weather sister La Niña, on local glaciers may not be ascertained for another 10 years or so. According to geologist Karl Ricker — who has been involved in monitoring the Wedgemount Glacier since 1975 and the Overlord Glacier since 1986 as part of a B.C. Institute of Technology program — glacier snouts require at least a decade to respond to heavier or lighter snow falls on their upper accumulation zones. Both glaciers have, however, been in retreat over the last decade, although they do not always show a similar response to local climatic fluctuations. The 1999 survey of the positions of the termini of the Wedgemount and Overlord glaciers was completed last month. They show that in the past year, Wedgemount’s snout continued its retreat by a further 5.6 metres, although that was a reduction over the previous year’s retreat of 20.3 metres when the glacier was hammered by the warmth of the El Niño oscillation. Ricker said the Overlord snout has advanced by 1.2 metres over last year’s position, although in 1998 it had retreated by a total of 12.1 metres. He said the data is inconclusive as far as indicating a general climatic trend because of the length of time it takes glacier snouts to respond to weather patterns. He said, however, Wedgemount does appear to have lost its protective winter snow cover much earlier this season, which has allowed him to record the continuation of a retreat. "The La Niña of 1999 has yielded an immediate variable response by our local glaciers but its long-term impact may be masked by the influence of El Niño in 1998," said Ricker in his report. The glacier monitoring program was started on Wedgemount in 1975 when the survey department of the B.C. Institute of Technology, under the direction of Bill Tupper, embarked on a large project to map many aspects of the glacier’s surface, as well as the lake, on an annual basis. In 1988, however, the program was cut back to monitoring only the snout. In 1986 snout surveys were started on the Overlord Glacier when it was discovered it had advanced significantly in the ’70s and early ’80s. Data on the two Whistler area glaciers are submitted each year to the World Glacier Monitoring Service based in Zurich, Switzerland. Information on several hundred glaciers from all continents are processed by this UN-supported organization.
