Thermo-erosion gullies in continuous permafrost regions where ice-wedge polygons are widespread contribute and change the drainage of periglacial landscapes. Gullying processes are causing long-term impacts to the Arctic landscape such as drainage network restructuring, permafrost erosion, sediment transport. Between 2009 and 2013, 35 gullies were mapped in a polygon terrace in the valley of the Glacier C-79 on Bylot Island, Nunavut (Canada), one of which was monitored for its hydrology. A gully (R08p) initiated in 1999 in a low-center polygon terrace. Between 1999 and 2013, 202 polygons over a surface of 28 891 m 2 were breached by gullying. Overall, 1401 polygons were similarly breached on the terrace in the valley before 2013. R08p is fed by a 1.74 km 2 watershed and the hydrological regime is characterized by peak flows of 0.69 m 3 s −1 and a cumulative volume of 229 662 m 3 for 2013. Historic aerial photography from 1972 and recent field surveys showed a change in the paths of water tracks and an increase in channelized flow in the gully area from none to 35% of the overall flow path of the section. The overall eroded area for the studied gullies in the valley up to 2013 was estimated at 158 000 m 2 and a potential volume close to 200 000 m 3 . Gullying processes increased drainage of wetlands and the hydrological connectivity in the valley, while lowering residence time of water near gullied areas.

A thermo-erosion gully has been monitored in the valley of glacier C-79 on Bylot Island since 1999. The main channel of the gully reached 390 m in length a few months after its initiation and grew between 38 and 50 m/year over the following decade, for an overall approximated average of 75 m/year. In 2009, the total gully length and area, including the main and relict channels, were 2500 m and 25 000 m2, respectively. Gullies affect snow accumulation, and therefore ground temperature, local water flow, and drainage. Sinkholes, gully heads, pools, baydzherakhi, tunnels, and collapses were grouped as a function of time since gully formation in that area. Sinkholes and tunnels were formed every year after gully inception, and baydzherakhi were found in 3–10 year old sections of the gully. Stabilization of the gully floor and sides took about a decade.