Uneasiness mounted along with uncertainty as Sunday's massive blackout grew in length while daylight waned and already-frigid temperatures began dropping further toward the -30 C mark.

Both Yukon Energy and Yukon Electrical Co. Ltd. continue to ask customers today to conserve energy and forego any unnecessary use of power.

Yukon Energy spokeswoman Janet Patterson said late this morning that with two hydro-turbines at the Whitehorse Rapids dam and all nine available diesel generators on line, the total capacity is still below the typical peak load at supper time.

Ed Sager of Yukon Electrical said customers are being asked to exercise restraint at least until the Aishihik hydroelectric dam is back on the system.

'One of the Aishihik units turned itself off, and when that happens, it is trying to protect itself from further damage,' Patterson explained. 'What we do not know is why it did that.

'I can't say at this point if there was any damage. They did happen to bring this Aishihik unit back on, but it just didn't go on.'

Patterson said while the Aishihik facility is staffed, additional personnel were dispatched Sunday afternoon to help identify and fix the problem.

There was, however, no word from Otter Falls by early this afternoon, she said.

Patterson said once the Aishihik unit shut itself down at 1:32 p.m.Sunday, the sudden jump in demand for the two Whitehorse hydro units operating caused them to shut down, and bring about a system-wide blackout for the Whitehorse-Aishihik-Faro grid.

The earliest return of power in Whitehorse was some three hours later. The longest was some eight or nine hours, though specific times from Yukon Electrical were not available this morning, as there has not yet been a thorough review of the blackout.

Some residents without any alternative heat source found friends and neighbours who did have power on, or simply bundled up and counted on crews responding to the desperate situation to have electricity back on as soon as possible.

With such an extensive blackout and the loss of Aishihik, it simply took time to re-energize the entire system in such a fashion as to ensure orderly restoration without threatening another system-wide problem, she explained.

For Yukon Energy, some 20 or 25 people were called in or arrived on their own to assist, and it was all hands on deck for Yukon Electrical.

The city's public works department topped off the staff of three transportation employees who were on shift with an additional 10 employees called in to make sure the city's water pump and sewage lift stations remained operational. Steps were taken to ensure traffic lights reset properly, and were reset, when power became available.

While most of the telephone communications remained unaffected as most are linked to back-up battery power, Granger and Copper Ridge customers did lose the service after batteries failed at 5:30 p.m. A back up generator was installed and the service was back at 7:40 p.m., officials said.

Compounding the system-wide blackout was the failure in Teslin, Haines Junction and Carmacks of back up generators large enough to power those communities on their own, the spokesman for Yukon Electrical confirmed this morning.

Sager said there may be a power squeeze during peak periods tonight, and until the Aishihik units are back on line, customers can expect the possibility of rotating outages.

'We always have that option,' said Sager. 'Today after five, if Yukon Energy said we need five megawatts of power, we would look to find the place where there is the less residential customers, like the Marwell area.

'It is possible, depending on the load, depending on the system capability. That is possible as long as Aishihik is off line and Yukon Energy does not have the sufficient capacity to meet the load.'

Yukon Energy president David Morrison said this afternoon, he was confident that with the rising temperatures, the current generating system will be able to handle demand if they don't lose any further capacity.

It looks like the trouble at Aishihik is one of distribution, and not a problem with the units themselves.

The two Aishihik units, the mainstay of the WAF grid in the winter, can produce 30 megawatts.

While Yukon Energy owns and operates most of the territory's generating capacity, Yukon Electrical is largely responsible for the distribution system.

At 8:23 p.m., said Patterson, Yukon Energy maximized its generation capability with 45 megawatts available.

'That is when we told Yukon Electric, This is all we got, and you guys are going to have to rotate outages.''

Patterson said it was her understanding there was only a need to shut down an area of Riverdale where power had been restored in order to light up a residential sections downtown.

It is the first time anybody can remember, since the 1998 closure of the Faro mine, the WAF grid has been so dependent on diesel generation, she said.

Though it is not without a cost.

Patterson said in addition to the three turbines in Whitehorse, the seven Whitehorse diesel generators are operational, as are the generators in Faro and Ross River.

To run all seven costs about $4,500 an hour, or $100,000-plus per day, she said.

Some have expressed concern about what they felt was a lack of information or reassurance through public and community radio announcements.

Doug Caldwell of the Yukon Emergency Measures Organization said this morning the EMO response was well underway, though the need to elevate the response with the establishment of an emergency centre never arose.

Once the first bit of electricity was restored, officials were confident addressing the problem was well underway, though the emergency response network remained activated well into the night.

'We had a two-hour, four-hour, six-hour and next-day plan,' Caldwell said.

He also reminded Yukoners it is their responsibility to have their own 72-hour emergency response plan to look after themselves and their families.

There are ways to provide safe and alternative methods of heat, for instance, he explained.