In the winter, folks in Tuk watch the sun set for the last time on November 28th and celebrate its return on January 13th. The average February temperature is –26°C. Lows regularly dip to the point of convergence between Celsius and Fahrenheit: -40°. Ski-Doos brap across the crust of snow on Tuk’s lakes and lands and ocean. The frigid Arctic breeze blows snow drifts flush with the coastline, creating a barely perceptible threshold between landfast ice and frozen soil, were it not for the orange life rings and overturned rowboats marking definitively, the edge of North America and the Arctic Ocean.

This fixed line between sea and shore is merely seasonal, however. On May 18th, the sun will rise above the horizon and circle the coastal hamlet continuously until finally setting for a brief hour on July 25th. Under the midnight sun, the sea ice will melt, and the Arctic Ocean will beat relentlessly against the permafrost bluffs along the Western Arctic coast, and the increasingly warm summer air will thaw ancient ice, causing cliffs to erode and massive swaths of land to slump into mudflows. For residents of Tuktoyaktuk, longer, warmer summers have been making life more difficult for the last 40 years.

As Richard Gruben, Vice-President of the Tuktoyaktuk Hunter and Trappers Committee puts it, Tuk is “a traditional community. Just about everybody here travels around and hunts off the land and fishes our waters.” Because of this, Gruben and other Tuk residents are especially aware of climate change and its impacts: Summer storms are more frequent and intense, animal migration habits have changed and the community must prepare earlier in the year to harvest beluga whale, which arrive three weeks earlier than they used to, says Gruben. But of all the many tangible climate change impacts, none may be bigger than coastal erosion and permafrost slump.

Though coastal erosion is a challenge for nearly every marine coastal community facing pressures of storms and sea level rise, it is particularly emergent for places like Tuk, built on permafrost. Wave action eats away at coastal bluffs, exposing ancient ice to melt in continuous daylight, threatening buildings and infrastructure, exposing artifacts and muddying the waters of the Beaufort Sea.

In 1982, the sea swallowed Tuktoyaktuk’s curling rink after a storm eroded permafrost that the seaside end of the building sat on. Ten years ago, a government building fell halfway into the ocean, and had to be moved back inland. Over the past 40 years, at least two homes have been completely swallowed by the waters. Today, the femur-shaped Tuktoyaktuk Island, which protects the harbor from the ocean, is now in danger. The guardian spit of permafrost is eroding at a rate of about 1.1 meters per year, and might cease to break waves by 2050.

Mayor Erwin Elias, a lifelong resident of Tuk, cites coastal erosion as the number one issue facing the hamlet.

“The harbor is the lifeline for the community. That’s one of the main reasons Tuk is where it is today,” said Mayor Elias. “We’re a traditional fishing village, and Tuk Island is a natural wavebreak for us. If we lose that, we will lose our harbor, and I think everything will be pretty rapid after that in terms of erosion.”

The banks of the freshwater lakes inland from the Beaufort Sea are also made of ice-rich permafrost. Permanent ice, frozen during the last ice age, gives the soil structure and keeps the water contained. But warmer summers deepen the portion of the permafrost around each lake that thaws annually, until the permafrost slumps away, creating receding bluffs that creep closer and closer to each lake’s edge. Eventually, the cliff wall meets the affected lake and water pours over the exposed black soil and ice. The rushing waterfall eats away at the bank as lake water and sediment rush downstream. The effects are immediate. A lake formed between 13,000 and 8,000 years ago transformed into a mudflat in less than a day.

Paul Voudrac, a recently retired government wildlife observer, 66, lives a two-hour drive south along the newly constructed Tuktoyaktuk-Inuvik highway in the regional hub of Inuvik.Every winter when he was a kid in the early ’60s, his dad would take his whole family on a trek from their home in Tuktoyaktuk, 112 kilometers east to their cabin on Tuktoyaktuk Peninsula. After the snow and freeze-up that used to happen in October, they’d make the four-day trip by dogsled to hunt and fish and trap around the Husky Lakes, a brackish estuary emptying into Liverpool Bay. When SkiDoos became popular in the late ’60s, travel time changed from days to hours. And changes to the landscape began to alter well-known trails.

Permafrost thawing and slumping suddenly met the edge of lakes with increasing frequency, eroding their banks and draining them. Instead of familiar open areas of ice and snow good for winter travel, Voudrac’s family was instead met with dense willow flats—making travel difficult, and disrupting long standing trails used by the Inuvialuit.

“On lakes we’ve traveled for years the willows rose up from the ground to about ten feet high, and we had to cut a trail through in order to get by it,” Voudrac recalls. “We were used to traveling where we went by. We had trails, one to the north, one straight to the west—always by the ice. And then we started seeing a lot of changes happening to the trails from Tuktoyaktuk. My dad passed away in 1973, and that trail west has been very little use since.”

Voudrac has noticed other changes, too—the massive, saline Husky Lake used to freeze over completely every year, forming 2.5 meters of ice in the winter months. In recent years, folks have begun to observe open water in the winter. Paul also joked that “thirty below used to be springtime weather for us. T-shirt weather. But now, you get down to about twenty below and you start feeling it. We’re spoiled, I should say. We can’t change as fast as the weather can.”

Permafrost is defined as any soil that remains continuously frozen for two or more years. If you were to dig down into permafrost on a summer day, you’d first break through an insulating dense mat of hardy tundra plants—sedges, grasses, rushes. Then, you’d reach the active layer: soil that freezes and thaws every year with the seasons. Below that is a mixture of rock, dirt and varying levels of ice that stays frozen year round. Go even deeper — anywhere between one and 1,500 meters depending on where you are, and you’d reach frost-free soil again, where geothermal heat warms the earth’s crust above freezing temperature.

As far as dirt goes, permafrost is also particularly sensitive to climate change. Increases in air temperatures increase the depth of the “active layer” of the permafrost, thawing ice and destabilizing the soil’s structure. Warming permafrost causes what are called retrogressive thaw slumps—landslides caused by the melting of ground ice in the permafrost. These slumps often form with a semicircular headwall, receding into the stable permafrost. Inside the half ring of exposed permafrost cliff of the headwall runs a black, boggy mudflow.