In the past 10 years or so, a great deal of attention has been directed at climate-induced air-temperature changes in the high latitudes. It has also been suggested that climate change would be intensified at high latitudes with increased greenhouse gases in the atmosphere and that, therefore, this region would be a good candidate for capturing changes through field measurements. There is no doubt that change is ongoing in many environmental processes: permafrost temperatures are increasing and in many cases the permafrost is thawing (Lachenbruch and Marshall, 1986; Romanovsky et al., 2002), maximum extent of winter snow cover is decreasing (Robinson, et al., 1993), sea-ice extent is at record minimums and thinning (Vinnikov et al., 1999), many glaciers are rapidly retreating (Dyurgerov and Meier, 1997; Thomas, 2001; Arendt et al., 2002), and lake and river ice forms later in the fall and melts earlier in the spring (Magnuson et al., 2000). Some of the documented change has occurred over long periods of time; however, the process seems to have gathered speed since the mid-1970s. It has also been hypothesized that a warmer climate would accelerate many of the processes in the hydrologic cycle, such as enhanced evapotranspiration and precipitation. This possibility has further heightened interest in high-latitude hydrology and acted as a catalyst for identifying possible trends in various hydrologic fluxes, primarily precipitation (as snow and rain), and runoff, to date.
In March 2004 several hydrologists convened at a workshop on 'Northern Research Basins Water Balance' in Victoria, BC, Canada. Water balance data from 39 experimental watersheds with over 500 years of cumulative water balance results were presented (Kane and Yang, 2004). Whereas some hydrologic relationships are readily apparent based on the cumulative data, what is clearly evident in the overarching picture is the difficulty of closing the water balance, even for these relatively small basins (0β’1 to 432 km 2 ). It is obvious that we are still struggling with the measurement of even the simplest hydrologic variables, such as precipitation. Further, storage terms and evapotranspiration can be just plain difficult to quantify. Measurements are often made at a time when the environment can be quite hostile; for example, the peak annual discharge event is usually accompanied by ice break-up. The end result is that we do not have good, high-quality hydrologic data for answering questions about climate change; and this is understandable, since our established data-collection networks were not initially developed with this task in mind.