Hold onto your hats. Stock market volatility could get worse, a widely followed technician says.

U.S. stocks hit a three-month low Wednesday morning amid concerns of slowing growth in China and the uproar over North Korea's claim to have tested a hydrogen bomb. By late morning, the was around 2,000.

On Tuesday, Bank of America Merrill Lynch's Stephen Suttmeier said the S&P is in danger of dipping below 1,965, a key technical level that could unleash a torrent of selling.

"In 2011, you had pullback that retraced 61.8 percent of the rally off the low and it was held," Suttmeier said on CNBC's "Fast Money,"

"To say that we have a top in place in the S&P 500, 1,965 needs to be broken [again]," he added. "That is significant for me because that's where the price structure differs vastly from the price structure of 2011 where you had advance-decline lines and on-balance volume breaking out and the market had not broken out yet."

Suttmeier warned that if the S&P 500 sinks below 1,965, then it may not bounce back — as it did in 2011 — and the market could reach lows of 1,870 to 1,820.

"If [1,965] can't hold, the risk of a deeper more traditional cyclical bear market would be in place," he said. "The cyclical run from 2009 is extremely mature and we're seeing signs of risk as we enter this year."

The decline in the S&P 500 is of little surprise to Suttmeier, who noted that other technical indicators had been week for months.

"Weak breadth shows the S&P advance-decline line is lackluster," said Suttmeier. The advance decline line — viewed as an indication of the market's overall health — has fallen since hitting new highs in November and December.

He also said technical volume indicators point to a market that has much further to fall.

"What this tells me is that the best case is 2,100 and then lower. The problem is that the indicators are rolling over and that's a big risk for equities as we enter 2016," he said.