"The failure to do that is something that could result in severe damage to the economy and to financial markets and it's just not something we should contemplate," he said
US stocks pared gains, while yields on 10-year Treasuries pushed higher
Dow Jones Industrial Average rose 341.11 points, or 1.01%, to 34,260.95, the S&P 500 gained 41.54 points, or 0.95%, to 4,395.73
A Wells Fargo spokeswoman did not immediately respond to a request for comment
US stocks rose slightly, while yields on 10-year Treasuries maintained an earlier decline; the dollar remained lower after the decision
The survey of 52 economists also predicted the US central bank would hold interest rates near zero through 2022 before delivering two quarter-point increases by the end of the following year
Wall Street is widely expecting that Powell, who was nominated for the role by President Donald Trump in 2017, will be renominated by President Joe Biden for another four-year stint.
Progressive Democrats want the Fed to take on a more expansive role in the economy, by beefing up efforts to bolster employment, heading off climate risk and addressing inequality
Data over the past week captured a worldwide weakening as infections hit travel and spending and worsen supply bottlenecks that are dampening manufacturing and trade
Markets continue to run ahead of fundamentals
On the contrary, flows into India may surge if the Covid situation remains in control, say experts
India must address risks to financial stability
Powell said US economy continued to make progress towards the central bank's benchmarks for reducing its pandemic-era emergency programs, but stopped short of signaling the timing for any policy shift
In a speech to the annual Jackson Hole economic conference, Powell indicated the Fed will remain cautious in any eventual decision to raise interest rates
The Federal Reserve will start dialing back its ultra-low-rate policies this year as long as hiring continues to improve
All the 11 major S&P sectors were up, with energy, materials and communication services jumping 1% each.
The broader markets, meanwhile, outperformed, rising for the fourth straight session
Spot gold fell 0.3% to $1,784.82 per ounce by 0705 GMT, while U.S. gold futures fell 0.3% to $1,785.00.
Investors are mostly waiting for the Federal Reserve's Jackson Hole symposium on Friday and what central bank chair Jerome Powell might say about U.S. tapering monetary stimulus
The STOXX index of 600 European companies, nudged 0.15% higher to 472.51 points, less than four points from its record high from earlier this month