Wild market swings like Monday's late-day reversal are becoming commonplace for a stock market that just last year enjoyed an extended period of remarkable calm.
Wall Street pros increasingly have been advising investors to get used to it. Headline risk abounds, and it's not just about the potential for a U.S.-China trade war and the perpetual stream of startling headlines out of the White House.
"Let's face it, the problems for the stock market, and risk assets in general, began long before this verbal trade skirmish between the USA and China," David Rosenberg, chief economist and strategist at Gluskin Sheff, told clients in his daily note Tuesday. "It all comes down to the simple fact that we are into a totally new and uncertain environment across a broad front."
Breaking it down, Rosenberg offered 10 reasons why volatility has returned:
Rosenberg advises investors to look for a technical signal — the "death cross" that forms when the S&P 500's 50-day moving average moves beneath the 200-day moving average. The index made a "golden cross" in mid-2009, in which the 50-day moves above the 200-day, just a few months after the market put in its financial crisis lows.
A death cross is likely soon, Rosenberg said.
"This is the major point — don't call the market," he added. "Let the market dictate to you what's going on — it is flashing something very critical, though classic, late-cycle features right now that deserves our focus and attention."
WATCH: One investor's take on how to play the heightened volatility.