Earlier this summer in the mountains southeast of Alaska's capital city, a thunderous roar of water and ice came tumbling down the Taku River.
The phenomenon caused by a glacial flash flood - or "jokulhaup" - swept full oil drums, pieces of old trapper's cabins, and giant trees into the ocean near one of Alaska's richest commercial fisheries.
Today, as American conservationist Chris Zimmer looks toward the Taku, he and others worry about what could happen if a similar event were to occur across the border near a proposed gold and copper mine in Canada where of toxic metal tailings are slated to be buried along a stream that joins the Taku.
The dispute over the proposed mine is symbolic of growing environmental tensions along the US-Canada border.
While the US has long been embroiled in disputes on the border it shares with Mexico, American relations with Canada have been in some ways more quiescent. Now, however, a string of proposed mines and natural gas developments in Canada's "wild West" province of British Columbia is creating new clashes reaching all the way to Ottawa and Washington:
• Alaskan commercial fishermen and Canadian native people are concerned about a proposal to reopen the Tulsequah Chief mining complex by a Vancouver company across the border from Juneau. They are concerned mining waste could impact fisheries and that access roads will disturb wild lands.
• Across the border from Montana, an auction is scheduled later this month to sell off drilling rights for coal-bed methane gas inside the Flathead River Basin. The anticipated pollution from the process has prompted protests downstream.
• Six miles north of Washington in Trail, B.C., a lead and zinc smelter, run by Teck Cominco Limited, is causing concern within the US Environmental Protection Agency over hazardous waste that has traveled down Columbia River and accumulated in Lake Roosevelt.
Yet concerns about pollution hardly flow one way. Canada says that proposed water diversion from flooded Devil's Lake in North Dakota could contaminate rivers that feed Manitoba's Lake Winnipeg.
Over the past century, no natural resource along the 5,000-mile border has left the US and Canada more united - and divided - than water. In 1909, the Boundary Waters Treaty delineated water rights, protecting both countries from contamination by the other.
Thousands of disputes followed over the years, prompting the fairly recent creation of a special body called the International Joint Commission (IJC) to act as an intermediary. But both nations must consent to IJC intervention, and so far British Columbia has balked at submitting the contested developments to review- a fact that has rankled US politicians.
Across the province, billions of dollars are at stake. It has an estimated 23 billion tons of undeveloped coal, 115 trillion cubic feet of gas, 90 trillion cube feet of coal-bed methane, and a vast boreal forest. Recent reports show that interest in mining is skyrocketing. Richard Neufeld, the provincial energy and mines minister resents the way his province is being characterized as a villain.
"Every morning when I get out of bed, I don't declare, 'Let's see what valley I can go ruin today,'" he says. "No one here desires to do stupid things. Our rigor with upholding environmental regulations is strong."
Conservationist Zimmer with the Transboundary Watershed Alliance says the pace and magnitude of development in British Columbia is proceeding too quickly and needs further study.
Mr. Neufeld counters that the IJC is merely a tool for "obstructionist environmentalists" in the US who want to shut down Canadian development.
The provincial government and a private mining company this year withdrew coal mine plans in the upper Flathead drainage at Cabin Creek, B.C. Yet in the coming weeks the province intends to auction off rights to drill for methane on nearly 100,000 acres near the Flathead and Elk rivers, an even bigger worry, say environmentalists concerned about large volumes of waste water.
The Flathead Basin is home to abundant wildlife, including the largest concentration of grizzly bears in southern Canada. Cabin Creek crosses into the US and forms the western boundary of the joint Waterton Lakes/Glacier National Parks before emptying into Flathead Lake.
Alaska Gov. Frank Murkowski says he is comfortable with B.C.'s environmental review, but his counterpart in Montana, Gov. Judy Martz (R), demands additional study. Montana's US Sens. Conrad Burns (R) and Max Baucus (D) back the call.
"If the Canadians are going to go forward with coal-bed methane drilling, then they need to meet US environmental standards ... because it impacts us," said Burns spokesman J.P. Donovan.
David Thomas, city councilman from Fernie, B.C., notes that officials from this coal mining and resort town recently passed its third resolution calling for a comprehensive ecological, social, and economic study. That request, along with one sent from the Chamber of Commerce in Kalispell, Mont., was rejected by Neufeld.
In Alaska, Bart Koehler, an activist with the Wilderness Society, says there's far more at risk than commercial fisheries. The mine also is being challenged by the Taku River Tlingit First Nation tribe, which opposes the tailings disposal plan and construction of a 100-mile access route to the mine across its land holdings.
"In your mind's eye, picture Yellowstone Park. The Taku watershed is twice that big without a single road in it," Mr. Koehler says. "Today, it has all the species of wildlife that were there before Europeans. But once the road goes in, it will open the door to more roads, more mines, more logging clearcuts, and more pollution."
Which is perfectly fine with Govenor Murkowski and Neufeld who say such industrial activity, as already happening in the lower 48, will create jobs and economic opportunity.