Adam Shell

USA TODAY

Wall Street endured another dramatic day as the Dow more than halved a 400-point drop amid a fresh slide in oil prices below the key $30 per barrel mark and continued fears about slowing global growth.

The rocky start to 2016 for stocks is continuing as investors contend with well-known yet persistent headwinds ranging from continued price declines in the oil patch, concerns about the impact of China's slowing growth on the U.S. and other world economies, and questions surrounding the pace -- and timing -- of interest rate hikes from the U.S. Federal Reserve.

The Dow Jones industrial average had lost as much as 401 points before climbing off those lows and registering a 178-point drop at the end of the trading day. Unfortunately, these kind of drops are not uncommon for the Dow in what has been a volatile 2016. The Dow had been on track for its worst point loss since a nearly 391-point plunge on Jan. 15.

Sliding 1.8% was the Nasdaq composite. The S&P 500 shed 1.4%, while the Dow's percentage loss was 1.1%.

Tech Five: Shares of Twitter sliding

In an attempt to avoid the rout in stocks, investors flocked to the perceived haven of long-term U.S. government bonds, which saw a price jump, but which sent yields, which move in the opposite direction, down to levels last seen in February of 2015. The yield on the 10-year Treasury note fell below 1.75%, levels last seen a year ago. Gold, another haven in tough times, saw gains of 3.3% to $1195.70 an ounce.

Last week, the S&P 500 fell 3.1%, leaving it down 8% on the year and 11.8% off its May 21, 2015, closing high.

Jason Pride, director of investment strategy at Glenmede, used a Super Bowl football analogy to sum up the U.S. stock market's current state: "The U.S. is facing 3rd down and long," he told clients in a report. "The expansion remains intact, but economic indicators are signaling mounting weakness on the margin."

Markets are in a state of confusion following a mixed U.S. jobs report Friday. While the 151,000 new jobs created in January fell short of estimates, positives such as the unemployment rate falling to 4.9% and a bigger-than-expected jump in wage growth kept the prospect of a Fed rate hike in March on the table.

Job growth slows in January as unemployment rate hits 8-year low

Wall Street fears a too-aggressive Fed will choke off growth and cause a recession and hurt corporate earnings, which are already under pressure from a strong dollar, the rout in the energy and commodity space and slowing growth around the globe.

Wall Street will be closely watching Fed chair Janet Yellen's two-day testimony before Congress starting Wednesday, as well as other comments from other Fed members this week, says Bill Stone, chief investment strategist at PNC Asset Management.

"Their comments will be parsed for clues regarding any action at the March meeting and the path of any future rate hikes," Stone told clients in a note before the start of trading. He also noted that investors are worried about further drops in the value of the Chinese yuan, following news that Beijing's foreign exchange reserves fell another $99.4 billion to $3.2 trillion in January.

Oil prices are falling sharply again Monday, with U.S.-produced crude down 3.1%, to $29.95 a barrel.

Wall Street is still debating whether the current stock market downturn is simply a serious price correction, defined as a drop of 10% but less than 20%, or the beginning stages of an official bear market, defined as a drop of more than 20% for major indexes like the Dow and S&P 500.

The Nasdaq composite is now flirting with a bear market, as it starts Monday down 16.4% from its late July record close. The small-cap Russell 2000 is already in bear-market territory, and heads into this week's trading down nearly 24% from its June 2015 peak.

The Dow and S&P 500, however, are sporting smaller losses, and kick off the new week down 11.5% and 11.8%, respectively. The Dow begins the week at 16,205, which is still more than 450 points higher than its Jan.20 intraday low for the year of 15,450.56. The S&P 500 starts the week at 1880, or 68 points above its low-point of the year on Jan. 20 of 1812.

Ari Wald, a technical analyst at Oppenheimer, says "caution remains warranted" amid the market's current struggles. He says the stock market and S&P 500 is either building a base for a short-term rally back up to the 1965 area or moving lower towards what he predicts is a level of roughly 1740, or more than 7% lower than Friday's close.

The stock market selling is just as intense in Europe Monday. The broad Stoxx Europe 600 is down 3.7%. In Germany, the DAX index is off 3.3%, while the CAC 40 in Paris is down 3.2%.