Workers have recovered four coffins from this excavation site in Dawson City, Yukon, since Nov. 4. ((Government of Yukon))

Cold weather in Dawson City, Yukon, is hampering archeologists' work at a site where human remains and coffins dating back to the Klondike Gold Rush have been discovered.

Yukon government archeologist Greg Hare and his team are in Dawson City after construction workers found the remains of a fourth person Monday during excavation for the town's new sewage treatment plant.

The site has already produced three other bodies and coffins. The bodies are believed to be those of hanged convicts from the 1890s Gold Rush in the Dawson area.

Hare told CBC News on Wednesday that there could up to seven other people buried in the area, which is larger than a football field and is believed to include two burial sites.

But efforts to recover the fourth body and search for others were being slowed by frigid conditions Wednesday. It was –30 C in Dawson City as of 1 p.m. PT, and Environment Canada forecast the daytime high to reach only –25 C.

Archeologists are running against the clock to do as much recovery work as they can before it becomes too cold to continue.

"With temperatures like this we've had to bring in a heater, a Herman Nelson heater, so we're trying to heat the earth that's been deposited there and keep this tent structure warm," Hare said in an interview with CBC Radio's A New Day. "But definitely, we're running out of time on this one."

Environment Canada forecasts temperatures in Dawson City will warm up slightly over the weekend and next week.

'It's going to take a while'

All four bodies uncovered to date have been in coffins, although remains of the fourth coffin were not found until Tuesday.

"We are certain that these are the people who were executed during the Klondike Gold Rush," Hare said.

A physical anthropologist arrived on Dawson City this week to begin analyzing the retrieved remains, which were taken away from the site. But Hare warned the identities of those who were buried will not be known right away.

"We don't operate at the speed of CSI, so it's going to take a while," he said.

"I'm not sure we'll ever say with certainty who the individuals are, but I think that we can go through a process of elimination and begin to put some kinds of identities on some of the people."

News of the discoveries have sparked local speculation about which Klondike convicts are buried in the area.

"All of Dawson is sort of buzzing with the news and the gossip that's surrounding the coffins, so everyone here is quite interested in it," Hare said.

"I think everyone has an interest in seeing this move forward."