A man who made millions as a short seller on Wall Street by betting against the odds has turned his sights from the U.S. economy to Vancouver real estate.

Former trader Marc Cohodes spent decades betting against housing "bubbles" before they burst. Now he has his eye, and his money, on the local housing market, and he has a warning to homeowners and first-time buyers.

"It's going to blow to complete and utter smithereens," Cohodes predicts.

"I think the market probably topped in the spring of '16 and I think all hell is going to break loose in Vancouver in 2017."

Cohodes is so confident in his prediction that he's betting against one of Canada's biggest alternative mortgage lenders, forecasting a housing crash similar to the one south of the border in 2008.

"I witnessed some of the U.S. housing fiasco here, and I said to myself, if I ever see it again, I should speak out louder than I did," he told CTV's Sarah MacDonald.

So this time he's speaking out, and his predictions are drastic.

Cohodes, who is now retired from trading, predicts that all of Metro Vancouver's multimillion-dollar homes will see their value plummet by as much as 50 to 80 per cent.

He noted that recent numbers already suggest a dip of between 15 and 20 per cent in some areas.

A Vancouver-area economist who spoke with CTV earlier this month about a dip in prices for detached homes says buyers and sellers may see another drop, but that Cohodes' dire prediction is unrealistic.

Tom Davidoff – who predicted a dip of 15 per cent when the foreign buyers' tax was introduced in Metro Vancouver in the summer – says homeowners may see their property values fall another 15 in 2017.

"That could absolutely happen," he said.

In a previous interview, the associate professor at UBC's Sauder School of Business said sales have been slow since the tax started, and that prices are ticking down as a result.

"I think we can say the market is facing very significant headwinds. We have the foreign buyers tax hitting an important part of the market. We've got new qualification rules for mortgages coming down for lower-end buyers," he said on Dec. 5.

But he cautioned that the market is hard to predict, especially with interest rates rising south of the border. If Canadian rates follow suit, and some have, it could push prices down even further across the country.

And the B.C. Real Estate Association says factors like the foreign buyers' tax could fuel a drop in demand and sales.

"It hasn't really hit yet, but we expect it to really start taking a bite out of sales in 2017," said BCREA economist Brendan Ogmundson.

He estimates the number of sales to dip 20 per cent, and the average home price to decrease by eight per cent.

The latest numbers released by the Real Estate Board of Greater Vancouver, published Dec. 2, shows that sales in November were down 0.9 per cent compared to the previous month. The data also showed sales this November were 7.6 per cent lower than the 10-year average for that month.

The benchmark price of all residential property types for the month was $908,300, down 1.2 per cent from October, but up 20.5 per cent from November of last year. Numbers for December and year-end totals will likely be released next week.

The forecasted price decreases have some recommending both buyers and sellers be cautious about entering a market that could quickly change.

"There's so much uncertainty over where prices are heading in Vancouver," Davidoff said.

While others suggest first-time buyers hold off on making a purchase entirely.

"Don't buy, don't buy, don't buy!" Cohodes advised.

With a report from CTV Vancouver's Sarah MacDonald