The Mackenzie River

Rising at the west end of Great Slave Lake in Canada's Northwest Territories, the Mackenzie River flows northwestward for almost 1100 miles to the Beaufort Sea. Un-dammed and winding through Subarctic and Arctic wilderness, its wide, braided channel is just the final conduit of a massive watershed that covers 20% of Canada, extending from northeast British Columbia, northern Alberta, northwest Saskatchewan and the western Yukon to the massive Mackenzie River Delta, the 12th largest on our planet. If one includes its most distant tributaries, this river system exceeds 2600 miles in length (the longest in Canada) and drains a watershed of almost 700,000 square miles.

To the southwest, the Peace and Athabaska Rivers rise on the east side of the Continental Divide in the northern Canadian Rockies; these large streams merge to form a large inland delta along Lake Athabaska, which drains to Great Slave Lake via the Slave River. Leaving Great Slave Lake, the Mackenzie River picks up meltwaters from the Mackenzie Mountains (to its west) via the Liard River system and then receives flow from Great Bear Lake, to its east, the largest lake in Canada. At its braided delta, just east of the Richardson Mountains, the Mackenzie discharges copious amounts of relatively warm, fresh, nutrient-rich water into the Arctic Ocean; this annual discharge, the 14th largest on Earth, dramatically affects the regional ecosystem, allowing boreal woodlands to extend well north of their usual range and increasing the diversity of plants and animals across the ever-changing delta. Beluga whales gather here in spring to molt in the mild river current and the countless, shallow lakes provide ideal breeding habitat for shorebirds, tundra swans and snow geese. Resident mammals include black bears, barren ground grizzlies, Arctic fox, Arctic wolves, caribou, moose, musk ox and a massive number of muskrats.

However, all is not well in this seemingly pristine wilderness. Dams on tributaries of the Mackenzie have reduced flow through its primary channel and are diminishing the annual floods that are crucial to the welfare of its delta ecosystem. In addition, worrisome levels of mercury have been found in the river over the past few years, the product of mining and power plant effluent across the watershed. Of course, as with other Arctic ecosystems, global warming may dramatically affect the natural diversity of this magnificent yet fragile landscape.

Eastern Sandhill Cranes

Most American birdwatchers associate sandhill cranes with the Great Plains and Western U.S., having seen large flocks at staging areas, such as the Platte River in Nebraska or the San Luis Valley in Colorado, or at wintering grounds in California, New Mexico or Texas. But there is a large and growing eastern population of sandhill cranes, composed primarily of the greater sandhill crane subspecies.

These cranes breed in the vicinity of James Bay, Canada and around the Great Lakes, from Minnesota and Wisconsin to Michigan and northern Ohio. On their migrations to wintering areas from southern Georgia to central Florida, they use two primary staging areas: the Jasper-Pulaski State Fish & Wildlife Area, in northwest Indiana, and the Hiwassee Wildlife Refuge, just NNE of Chattanooga, Tennessee. Of course, migrant flocks may be seen in wetland areas and agricultural fields anywhere between their breeding and wintering areas and the cranes may shorten their travels if mild conditions persist and they encounter a plentiful food supply.

Non-migratory populations include the Florida sandhill cranes, found from the Okefenokee Swamp to the Everglades (with the greatest number on the Kissimmee Prairie, north of Lake Okeechobee) and the endangered Mississippi sandhill cranes, found on or near the Mississippi Sandhill Crane NWR, along I-10 in southern Mississippi; the latter population currently numbers about 110 cranes. Another non-migratory population of sandhill cranes inhabits Cuba. All sandhill cranes, whether found in the eastern or western U.S., are threatened primarily by habitat loss, the result of marsh drainage, stream water diversion or agricultural development.

The Arctic Falcon

Gyrfalcons are the largest and most powerful falcons on our planet, inhabiting Arctic and Subarctic regions of the globe. Those that live near or above the Arctic Circle are white or pale gray in color while more southern subspecies have various degrees of gray or brown in their plumage.

Solitary for much of the year, adult males and females pair up in March and a clutch of eggs is laid by late April, usually on a bare rock ledge or perhaps in an abandoned raven nest. Both parents incubate the eggs and, within two weeks of hatching, the downy young are left to endure the harsh northern climate while the parents hunt for food; it is then that gyrfalcons are most vulnerable to predation, usually by ravens, skuas or Arctic fox. Those that survive to adulthood have little to fear from natural predators; swift, powerful and agile, they are imposing rivals and may live for 20 years or more.

Gyrfalcons feed primarily on ptarmigan but also attack geese, ducks, gulls and a variety of Arctic songbirds; tundra residents such as Arctic hares, ground squirrels and lemmings are also potential victims. These magnificent raptors, in the style of great white sharks, initially stun their prey with a traumatic collision or chase them to ground before making the kill. During the colder months, gyrfalcons are known to hunt along the pack ice, oblivious to the frigid conditions; though nonmigratory, a few may turn up across the northernmost U.S. in mid to late winter.

Maria Visits Newfoundland

After lolling about the Caribbean for a week and then passing west of Bermuda, Hurricane Maria has been racing northward and is expected to strike Newfoundland. The powerful storm will streak across the eastern half of that island province and the Avalon Peninsula should bear the brunt of her 80 mph winds.



Surrounded by the chilly waters of the North Atlantic, Newfoundland is relatively immune to hurricanes and tropical storms; indeed, cold water is one of the major factors known to weaken tropical cyclones. Nevertheless, Hurricane Maria is moving northward at a rapid rate, swept along by an advancing cold front, and is forecast to retain Level 1 traits when she reaches southeastern Newfoundland. After raking this Maritime Province, Maria is expected to dissipate south of Greenland.



As local residents prepare for the storm, one wonders if Jim Cantore is on a flight to St. John's. For the king of weather broadcasting to miss such a rare event is almost unthinkable. After all, we have now passed the peak of the 2011 hurricane season and the opportunity to report from the driving rain of a land-falling storm is rapidly fading.

Vancouver Island Earthquake

Along the Pacific Coast, from southern British Columbia to northern California, three small tectonic plates lie between the Pacific and North American Plates. The Juan de Fuca Plate is the largest, stretching from the center of Vancouver Island to the southern border of Oregon, while the Explorer Plate sits north of it and the Gorda Plate lies off northern California; all three, like the Cocos Plate off Central America and the Nazca Plate along the west coast of South America, are remnants of the oceanic Farallon Plate, most of which has since subducted beneath the North and South American Plates.

On the west side of the three plates, they are spreading from the Pacific Plate along a broken oceanic ridge while, on their east side, they are subducting beneath the North American Plate. Between the spreading zones, each plate also has a transform-fault margin with the Pacific Plate, where the plates are scraping against one another; in addition, horizontal (east-west) faults form the boundaries between the Juan de Fuca Plate and its smaller neighbors. In this complex tectonic region, earthquakes may thus be generated at the subduction zones, along the transform faults or at the faults that separate the three plates.

Yesterday's 6.4 magnitude quake occured off the west coast of Vancouver Island, along the subduction zone and very near the margin between the Explorer and Juan de Fuca Plates. Rather shallow (14 miles deep), it was felt as far away as northern Washington but, fortunately, did not produce significant damage. Of course, there is always the potential for strong quakes in this region and those that occur along the subduction zone could produce a catastrophic tsunami. Hopefully, regularly occuring weak quakes might diminish the risk for such an event.

Glacial Lake McConnell

Near the end of the Pleistocene, about 11,800 years ago, a massive lake formed across the Northwest Territories of Canada, extending southward into northeast Alberta and northwest Saskatchewan. Occupying a broad basin between the mountains to the west and the retreating Wisconsin Glacier to the east, its shape and size changed continuously, a balance between the inflow of meltwater and evolving drainage patterns due to glacial deposits, ice dams and periodic floods. The maximum extent of Lake McConnell, reached about 10,500 years ago, was 210,000 square kilometers (about 2/3 the size of glacial Lake Agassiz, to its southeast).

Inflow to Lake McConnell came primarily from the lobes of the continental ice sheet but also from mountain glaciers to the west and directly from Lake Agassiz via a corridor now occupied by the Clearwater and lower Athabasca Rivers; indeed, geologic evidence suggests that these large glacial lakes were intermittently connected and that water flowed in either direction, depending on the region's changing hydrology. At times, Lake McConnell drained southeastward into Lake Agassiz while, during other periods, the connected lakes drained northwestward, into the Arctic Ocean via the MacKenzie River. Eventually, as the ice retreated and the land rebounded, this connection was lost and both lakes began to diminish in size.

While Lake Winnipeg is the primary remnant of Lake Agassiz, a trio of Canadian lakes have been left in Lake McConnell's wake: Great Bear Lake, the largest in Canada, Great Slave Lake, the deepest in North America (2014 feet), and Lake Athabasca. All three of these postglacial lakes now drain to the Arctic Ocean via the MacKenzie River system.

Great Gray Owls

One of the least conspicuous birds in North America, the great gray owl inhabits the boreal forests of Alaska and Canada and the mountain forests of the Cascades, Northern Sierra Nevada and Northern Rockies; during the winter months, they may also be encountered in Minnesota and northern New England. Preferring dense, coniferous woodlands, they hunt primarily at night but become increasingly crepuscular or diurnal during the colder months of the year; it is then that they are most often observed, perched on a limb that overlooks a forest clearing. While this owl is seldom seen, its deep, resonant hoots often echo through remote northern forests.

Though great grays are our largest owls by length and wingspan (the latter may be up to 5 feet), they are not as heavy as great horned owls; their large head and prominant, ringed facial disc accentuate their size and make their yellow eyes appear to be small and closely spaced. Despite their size, great grays are not overly aggressive and feed primarily on small rodents (mice, voles, hares), grouse and songbirds.

Adult great gray owls have little to fear from natural predators (lynx are among their few adversaries) but their young (born in mid-late spring) may fall victim to goshawks, fishers, wolverines, lynx or bears. Indeed, the adults are more endangered by the activity of man, who drains the bogs and logs the forests that provide refuge to this ghost of the Great Northwoods.