A deluge of rain made for a treacherous start to Melbourne Cup day, forcing delays to races and trains to Flemington Racecourse, and leading to calls for the $7.3 million feature race to be cancelled.
A small section of roofing also collapsed while large parts of the track have also been flooded
The area was drenched with more than 46mm of rain falling on Flemington before 2.30pm (NZT), prompting fears jockeys and horses were at risk of injury.
The track was downgraded immediately after Race 1 to a Heavy 8 and Race 2 was pushed back to a 1.40pm start.
Race 4, the Ronald McDonald House Charities Plate, was able to jump on-time at 2.40pm. The track was also upgraded to a Soft 7 following Legend of Condor's win in the Schweppes Flemington Fling, the fifth race of the meeting.
Jockeys complained they were unable to see at times during the first race of the meeting and Channel 7's Hamish McLachlan said officials were refusing to walk on to the track because the conditions were too dangerous.
"Right now, all of the strappers have taken the horses underneath, they've decided not to bring them out. It's too wet and too dangerous — there has been thunder and lightning," McLachlan said. "It's a Cup that I've not seen before."
Trainer Richard Freedman, who has Auvray in the Cup, said the conditions and the downgraded track have completely changed the outlook for the $7.3 million feature race.
"I tell you what, this rain, it will change everybody's tactics too," Freedman told Channel 7.
"It has changed the whole race meeting. Whatever the tips were before the rain came, just throw them out the window and start again."
Earlier, jockey Mark Zahra should have been celebrating piloting Bella Rosa to a win in the first race — but was instead left lamenting the awful conditions and the impact it will have in the Melbourne Cup.
Zahra pushed home on-board Bella Rosa to win the Group 3 1000m Bumble Stakes ahead of Lankan Star and favourite Champagne Boom.
However, when interviewed in the misty conditions on track immediately after his win, Zahra was scathing of the dodgy Melbourne weather.
"The weather's obviously very bad," he said.
"Geez, I tell you it's close to an eight right now. It's probably more of a feel because of the surface water but if it keeps running like this in that race, you'd think it would be as bad as it gets for the Cup."
The delayed race meeting also followed public concern from jockeys who complained they were unable to see at times during the first race of the meeting.
A small section of roofing collapsed in the Flemington press room after water made its way in, and there has also been areas of flooding around the track, including in the horse tunnel.
"We have all hands on deck, people attending to it and we're hopeful it won't present any further problems," Chief steward Robert Cram told racing.com.
Channel 7 racing commentator Jason Richardson said stewards would have to consider a major delay to allow track staff to aerate the entire track to allow some of the surface moisture to be absorbed.
He said one slip from a horse is all it could take for jockeys to pull the pin on the meeting, citing "unsafe conditions".
"No (the rest of the day won't get called off), they have a choice of trying to aerate the track to try to get the water to soak in or we have a delay and try to let the showers pass and try to see if the water will soak in."
The chaos extended beyond the track with suites inside Flemington reportedly leaking from the ceiling.
There are also ongoing major service delays across the Melbourne public transport system.
According to reports, racegoers have been informed to walk from a nearby station after flooding at Flemington Racecourse Station.
It left racegoers wrestling with the option of leaving the track to find some dry shelter.
Terry Evans, who has been working as a bookie for the Melbourne Cup since the early 80s, says today is the worst he's seen in more than 40 years.
"Since 1976 when Ven der Hum won it's never been as bad as this," he told news.com.au from under his umbrella. "It's just too wet to come out."
Paul Thompson, who has worked more than 36 years at Flemington, says he's hardly received a bet all morning.
"There has been three or four days similar to this in the past, but the rain was well spaced out," he said. "This is solid rain at the wrong time of the day.
"People are deciding whether they will come or not, it's very hard to say yes to attending Melbourne Cup when you look outside and there's heavy downpours like this."
Meanwhile, organisers have said they remain confident the feature race will go ahead.
It would take a lot for the Melbourne Cup meeting to be postponed with visibility and lightning the only reasons the jockeys wouldn't ride.
Flemington's Super Saturday meeting in March 2010 was abandoned due to a storm after the Newmarket Handicap was run.
In 1976 a storm swept through Flemington yet the race was still run with jockeys caked in mud.
Racecallers couldn't identify the runners until the closing stages.
Jockeys though these days have greater respect for safety issues and often vote to abandon meetings due to visibility.
Chief steward Robert Cram said the rain should ease in the next hour and he's confident the Melbourne Cup will be run at 3pm.
The other reason meetings have been abandoned have been due to high winds.
Despite reservations about the meeting being in danger, Racing Victoria stewards are confident that the wild weather will clear and that the Melbourne Cup will be run on time.
Chief steward Robert Cram says alterations have been made but that the rain and racing program will continue to be monitored throughout the day.
"We've been in contact with the Bureau (of Meteorology) and they've informed us that the rain will continue over the next hour but will clear," he said.
"And we'll have clear space after that. Given that information and looking at the radar, we've determined to delay the second race and the third race, to give us room for assessment for the further program on the day.
"Our aim is to run the Cup at 3pm if possible."