Norman Wells (Grid)

General Information

Created: 2014-01-23 10:47:38
Modified: 2014-01-23 13:35:06

Active: No
Site:Mackenzie River
CALM-Code:C11 B
Responsible Countries: Canada,
Timezone:UTC/GMT -07:00 hours
Vegetation Type:Coniferous Forest
Responsible Person:Mark Nixon
Offset: m

Years of record (a)



Min Thaw (cm)(b)



Max Thaw (cm)(b)



Thawing Degree Days (c)




The active layer monitoring system extends from Fort Simpson, Canada in upper Mackenzie River valley to the Beaufort Sea coast at North Head, Richards Island, Canada.  Records start in 1991, 92 or 93 and continue.

Maximum annual thaw penetration and maximum heave and subsidence of the ground surface is measured using a modified version of a frost tube developed by Mackay (1973).   The device is a removable water-filled clear plastic observation tube, 2 cm in diameter, and ~2.5 m long inside a ~2.5 cm diameter, heave resistant access tube (Tarnocai et al 2004) long enough (~4 m) to be anchored in permafrost upon installation.  The ice-water interface in the observation tube corresponds to the frost table in the surrounding ground.  A 3 mm diameter coloured glass  marker, dropped into the tube each year prior to time of maximum thaw, rests on the ice surface, descending during the thaw season to be trapped at maximum depth on freeze back in late summer or fall.  Maximum heave and subsidence is recorded between observations by a scriber attached to a weighted sleeve around the outside of the access tube, scratching a painted surface either side of a reference mark (renewed at each visit).  Tubes were installed using a light weight pump (~10 kg, maximum discharge 100 litres/min).  The active layer is defined as the thaw recorded in the thaw tube, minus the height of the tube above the ground surface at maximum surface subsidence, assumed to occur about the time of maximum thaw.

Snow pack observations were taken during March or April, and are reported as a range of values from all the observations at the site.

Many of the thaw tube sites are also instrumented with automatic air and ground temperature loggers (Tarnocai et al 2004).  At some 40 sites, a 6-plate 12 cm diameter radiation shield (R.M. Young, model 41301-5) was mounted 1.5 m above the ground surface and air temperatures are measured by a thermistor in the shield that is connected to a single channel miniature data logger in the lower part of the mast (see Fig. 5 in Nixon et al., 1995).  A similar miniature data logger with internal sensor is buried near the base of the air temperature mast at a nominal depth of 3-7 cm to measure near-surface ground temperatures.  Two types of miniature data loggers have been used: HOBO loggers (Onset Computer Corp, USA.), range -37o to 46oC, resolution 0.25oC and Minilog loggers (Vemco Ltd., Canada), -50o to 40oC, resolution 0.3oC. Temperatures are recorded every 2 to 6 hours for a year or more before servicing.

Data provided are from 10 IPA Circumpolar Active Layer Monitoring sites. 

Additional metadata, data, and maps are available through Canadian National Permafrost Databases 


Permafrost Zone:Discontinuous
Vegetation:Mixed spruce forest-feathermoss
Landform:Fluvial terrace on till
Lithology:Histic Eutric Turbic Cryosol / Sandy silt (30 cm)
Description:General description of soil moisture : moist
Access Timeseries
Bibliographic References
(1976). Ice-wedges as indicators of recent climatic change, western Arctic coast. In Current Research 1976-A, Geological Survey of Canada, pp. 233-234.
Nixon, F.M., Taylor, A.E., Allen, V.S. and Wright, F.(1995). Active layer monitoring in natural environments, lower Mackenzie Valley, Northwest Territories. in Current Research 1995-B, Geological Survey of Canada, pp. 99-108.
Nixon, F.M. and Taylor, A.E. (1994). Active layer monitoring in natural environments, Mackenzie Valley, Northwest Territories. in Current Research 1994-B, Geological Survey of Canada, pp. 27-34.
F. Mark Nixon and Alan E. Taylor (1998).Regional Active Layer Monitoring Across the Sporadic, Discontinuous and Continuous Permafrost Zones, Mackenzie Valley, Northwestern Canada; in proceeding of 7th International Conferenece on Permafrost, Yellowknife.
Nixon, F.M. (2000). Thaw-depth monitoring. in The Physical Environment of the Mackenzie Valley, Northwest Territories: a Base Line for the Assessment of Environmental Change, (ed.) L.D. Dyke and G.R. Brooks; Geological Survey of Canada, Bulletin 547, p. 119-126.
Wolfe, S.A., Kotler, E., and Nixon, F.M. (2000). Recent warming impacts in the Mackenzie Delta, Northwest Territories, and northern Yukon Territory coastal areas; in Current Research 2000-B1, Geological Survey of Canada, 9 p. (online;
Smith, S.L., Burgess, M.M. and Nixon, F.M. (2001). Response of active-layer and permafrost temperatures to warming during 1998 in the Mackenzie Delta, Northwest Territories and at Canadian Forces Station Alert and Baker Lake, Nunavut; in Current Research 2001-E5, Geological Survey of Canada, 8 p.
Nixon, M., C. Tarnocai and L. Kutny. (2003). Long-term active layer monitoring: Mackenzie Valley, northwest Canada; in M. Philips, S. Springman and L.U. Arenson (eds.), Permafrost, Vol. 2, A.A. Balkema Publishers, Swets Zeitlinger, Lisse, The Netherlands, pp. 821826.
Charles Tarnocai, F. Mark Nixon, Les Kutny. (2004). Circumpolar-Active-Layer-Monitoring (CALM) sites in the Mackenzie Valley, northwestern Canada; Permafrost and Periglacial Processes, Volume 15, Number 2, pp. 141-153.
Dyke, L.D., 2000. Stability of permafrost slopes in the Mackenzie Valley; In The Physical Environment of the Mackenzie Valley, Northwest Territories: A Base Line for the Assessment of Environmental Change, Dyke LD, Brooks GR (eds). Bulletin 547, Geological Survey of Canada, p. 161169.
(1975). The stability of permafrost and recent climatic change in the Mackenzie Valley, N.W.T.. In Report of Activities, Part B, Geological Survey of Canada, Paper 75-1B, pp. 173-176.
Quinton WL, Shirazi T, Carey SK, Pomeroy JW., 2005. Soil water storage and active-layer development in a sub-alpine tundra hillslope, southern Yukon Territory, Canada; Permafrost and Periglacial Processes, 16: p. 369382.
Waelbroeck, Claire, Monfray, P, Oechel, W.C., Hastings, S. and Vourlitis, G. (1997). The impact of permafrost thawing on the carbon dynamics of tundra. Geophysical Research Letters, 24, 229-232.
Edlund, S.A., Alt, B.T. and Young, K.L.(1989). Interaction of climate, vegetation, and soil hydrology at Hot Weather Creek, Fosheim Peninsula, Ellesmere Island, Northwest Territories. In Current Research 1989-D. Geological Survey of Canada, Ottawa, Ontario, pp. 125-133.
Kokelj S.V. and C.R. Burn, 2005. Geochemistry of the active layer and near-surface permafrost, Mackenzie delta region, Northwest Territories, Canada; Canadian Journal of Earth Sciences, 42(1), p. 37-48.
Mackay, J. Ross (1973). A frost tube for the determination of freezing in the active layer above permafrost. Canadian Geotechnical Journal, 10, 392-396.

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Longitude:-126.46888889 °
Latitude:65.19305556 °
Elevation:61 m
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