Clouds, Weather and Pollution

Records of visibility and days with various types of weather are not published for Old Crow. The following is a brief discussion of cloud regimes and some of the weather issues which can be discussed in general terms.

Cloud

Three years of summer day time cloud observations are given in Wahl et al. 1987. They show maximum cloud cover in October, probably due to synoptic activity, and only 4 tenths cloud in April when the atmosphere is still dry due to the presence of the continental high pressure system (Table 7.9). This is similar to the annual pattern at Komakuk and Shingle Point although there is an indication of lower summer cloud at Old Crow than on the coast which is what would be expected from its sheltered continental position. Lower inland cloud cover has also been reported by field parties (Pearson and Nagy 1974, Martell 1988, Russell et al. 1988).

Visibility

The best visibilities would be expected in the March-April period when the atmosphere is very dry. In the Old Crow Flats the wetlands might provide moisture for a fall maximum in low visibility due to fog.

Blizzards

Blizzard conditions are officially said to exist if the following four weather elements occur simultaneously: snow or blowing snow, winds 40 km/hr or greater, visibility 0.8 km or less, and temperatures below -12.2EC. Blizzard conditions would be considerably less frequent in the Old Crow Basin than on the north coast due to the fact that extreme cold weather in the Flats is accompanied by very low wind speeds and many of the winter storms are warm storms with temperatures just below freezing. It is likely that on occasion cold coastal storms enter the Flats through the Blow River Pass or one of the other river valleys. These storms might produce blizzard conditions in Vuntut National Park but there are no data from the area and even the Old Crow wind record is only two winters long. Traditional knowledge and community monitoring programs will help determine the nature of the winter storm regime in the Park area. Frequent blizzards in the Eagle Plains area (Henry personal communication) are possibly due, on a meso-scale, to the exposed ridge location and on a synoptic scale, to the broad expanse of the Peel Plateau which is not as well protected from storms and strong atmospheric flow as is the sheltered Old Crow Basin.

Whiteout

Burns (1972) discusses arctic whiteout, stating that it is an optical phenomena which appears to the observer as a uniform white glow. Shadows, horizons and clouds become indiscernible and one's sense of perspective is lost. It is extremely hazardous to travel in these conditions. They are most frequent in late winter, early spring, and autumn. Low sun angle, a clean snow surface and uniform low cloud combine to produce these conditions. The presence of fog, ice fog, or blowing snow can produce similar effects but are not technically whiteouts.

Flying Weather

As access to Old Crow is by air and much of the tourist travel and scientific work relies on air support, the frequency of flyable conditions is important, but no published data are available from which to evaluate this factor.

Air Quality, Atmospheric Pollutants and the "Cold Condensation" hypothesis

Maxwell (1982) and Wahl et al. (1987) discuss the potential for air pollution in the Arctic. The State of the Yukon Environment report points out that the Yukon’s major sources of air pollution are from the combustion of fuels and open burning of wastes (Environment Canada 1996a). Fine particles can be trapped in the air over a community during the periods of cold calm stagnant air. These same particulates can also result in the formation of ice fog.

Barrie and others (Barrie et al. 1985; Rahn and McCaffrey 1980) have been studying the transport of pollutants to the arctic from industrial sources in Europe, Asia and North America since the 1970's. Metals, particularly cadmium, mercury and lead and radionuclides (radioactivity) enter the northern Yukon by long-range transport (Barrie et al.1992). These are found concentrated in the skin and muscle of marine mammals and the organs of undulates (caribou livers and kidneys). High levels of cadmium can also be due to natural sources and varies with the age of the caribou, being concentrated in the animals over the years (see also Figure 7.21b).

Recent concerns have been focused on the long range transport of organochlorines (PCBs and DDT) to the arctic by what is being called the cold condensation. The cold condensation hypothesis (a suggested theory) suggests that these and other volatile chemicals (also called persistent organic pollutants POPs) vaporize in the warm regions of the world and are transported to colder areas where they condense and are deposited as precipitation (see also Figure 7.21b). In theory this process would eventually lead to concentration of these dangerous chemical pollutants in the coldest regions of the world. Recent studies show that the more volatile types of organochlorides (those which are less chlorinated) increase with increasing latitude (Weis and Muir 1997) and with increasing altitude (Blais et al. 1998). (Other less volatile chemicals show a decrease with latitude and distance from source.) A study of days with elevated levels of toxephane (a organochloride) in the atmosphere over Tagish in the central Yukon showed that when air reaches the Yukon from industrialized areas such as Russia or the American mid-west, regions of heavy past use of toxaphene, it contained more of this chemical than air which had traveled for long distances over the ocean or originated in wilderness areas of Canada (Bailey et al. 1995). The state of the Environment report published in 1995 suggests that, at that time, the decrease in use of these chemicals counterbalanced the concentrating cold condensation effect (Environment Canada 1995). There is, however, continued concern regarding the potential for contamination of the arctic ecosystem and particularly the traditional food supply.

In June 1997 The Arctic Environmental Strategy - Northern Contaminants Program (NCP) issued a report entitled Canadian Arctic Contaminants Assessment Report (CACAR), a culmination of six years of scientific research and more than 100 studies. This document is reviewed and summarized by Kieth (1998) and Frugal and Kieth (1998) in a issue of Northern Perspective devoted to the discussion of "Arctic contaminants: an unfinished agenda". Norma Kassi, who was raised on Old Crow Flats and is now Environmental Co-ordinator for the Council of First Nations writes about the changes that have taken place in the Old Crow Flats.

"My grandfather said to me, " you know, some day when you’re a woman you’re going to see a lot of changes. When there’s only loons out there, you’re going to know then that there’s something wrong with the land and with the weather." (Kassi 1998). She stresses the need for global action and inclusion of indigenous people in process of restoring health to the Arctic.