Brad Pillans has seen the lake disappear and reappear over the decades, from family boating trips in the '60s to his current repository of leading research which includes trends dating back millions of years.

Lake George is also called Weereewa, meaning "bad water" in Ngunnawal language, owing to its muddy and salty waters.

"It's muddy because it's very shallow and the wind stirs up the mud on the lake floor very easily," Professor Pillans said.

A significantly wet November and December helped the lake stay full through summer.

The Bureau of Meteorology said the total rainfall around the region was at least 50 per cent above the January average which has added to the lake's depth.

"It really does look like a proper lake now," Professor Pillans said.

He said this season's abundant showers had reduced the amount of water usually lost by evaporation. He explained water falling directly on the surface of the lake immediately contributed to how deep it would become.

"The water level rose by 12 to 15 centimetres over the course of those wet weeks. In between, we had a dry period in mid December, where we had no rain for a couple of weeks, and the water level dropped by eight centimetres," he said.

"So the water level can fluctuate by something like a centimetre a day. Either down if there's no rain or because of evaporation, or up if there's rain over a few days."

At present, at its deepest point, Lake George is 2.9 metres deep according to the researcher's latest measurements which he takes every one to two weeks.

"We keep a close record of how the water level changes and it changes a little bit from week to week, depending on the rainfall," Professor Pillans said.

"The lake reached a maximum of 3.1 meters in November 2022, after three very wet years, and since that time it's been generally falling."

Since evaporation is always higher in summer because of warmer temperatures, the water level which would typically fall has been at this level for nearly 18 months.

"That's quite unusual in recent times," Professor Pillans said. "The water level to be as deep as about three meters is quite special."

The geologist said the lake's water level is than three metres 75 per cent of the time gauging from records stretching back 200 years. The last time it reached this level was in 1994 for about a year, and before that in 1976.

In the 50s and 60s, the lake had been consistently at a depth of four and half metres for more than a decade. At this point, Lake George apparently contained more water than Lake Burley Griffin.

This would lead to occasional flooding on the federal highway before it was made into a dual carriageway and raised to the level it is now.

"I can remember in the 1960s, when I first came to Canberra, the water would flood across the road near Collector," Professor Pillans said. "I actually learned to water ski on Lake George. It was quite a popular place to take boats and sailing boats as well."

Before Lake Burley Griffin was filled up with water, the Canberra Yacht Club was based at Lake George.

Most weekends back then had hundreds of people in sailing boats, in little fishing boats or having a picnicking along the edge of the lake.

"There didn't seem to be any particular rules in those days. People just drove out there and backed their trailers off the highway down to the lake and launched their boats," Professor Pillans said.

The short answer is yes. But if the Lake George has no streams where do the fish come from?

"People used to wonder how the fish reappeared in the lake after it had been dry. I heard stories when I was young that that fish were brought in by pelicans," he said.

Professor Pillans didn't know if this was true. But he could say with certainty Lake George was stocked with fish in the 1950s. It was then that people released Murray Cod into the lake for the purpose of having fishing.

"Native fish and other fish too can survive in the creeks that flow into the lake even when the lake has next to no water in it," he said.

"They'll always be a pool of water somewhere where small fish can survive, and once it fills up, those fish will breed and it'll take a few years but the likelihood is that there'll be fish to be caught in another 12 months.

"I can remember lots of people fishing out there but I don't think they were much good to eat. I think people just enjoyed the pleasure of catching them."

He said fish like carp loved muddy water and would naturally breed a lot in the lake.

The lake rests on Crown land and is often leased to local farmers when it's completely dry for grazing of sheep and cattle. But the professor said this was not particularly good for the lake's ecosystem.

While the lake is relatively accessible and shallow now, it is not necessarily safe to go swimming or fishing.

One of the earliest tragedies recorded on the lake happened in July 1956. A group of Royal Military College cadets from Duntroon drowned in the lake after their boat capsised. A combined search operation ensued to find the bodies of the cadets but only one was found.

Professor Pillans said storms would cause conditions on the lake to change quickly after which the waters would become quite rough.

"There have been a number of drownings over the years, sadly. As long as you're sensible and take notice of the weather then you should be safe enough," he said.

The lake is also a popular site for paragliders when it's dry. People love to enjoy excellent views of the inland terrain but it's uncommon now as some gliders prefer not to land on water.

"Paragliders would launch off the hill just near the highway where the Weereewa Lookout is and it could be quite spectacular. There would be several paragliders in the air soaring over the lake," the professor said.

Artists have also found inspiration in Lake George. In 2010, Alan Aston transported four fibreglass zebra sculptures on the completely dry yet muddy floor of the lake.

It was sensational. They were named Stopper, Reviver, Surviver and Dasher. The inanimate creatures were posed to look like they were naturally grazing, and soon a calf was added to join the dazzle.

The lake, without inlets or outlets, completely at the mercy of rain, has been a topic of curiosity among all who know of its vanishing acts.

So is Lake George going to stay a while longer or is it going to disappear again?

"The answer to that is in the weather and depending on how wet this year is... I'd like to see the lake stay for a while," Professor Pillans said.

"There are conflicting predictions as to whether we might get more or less summer rain and that will probably determine whether we have a lake for another decade or not."