WASHINGTON — The economic catastrophe caused by the viral outbreak likely sent the U.S. unemployment rate in April to its highest level since the Great Depression and caused a record-shattering loss of jobs.

With the economy paralyzed by business closures, the unemployment rate likely jumped to at least 16 percent — from just 4.4 percent in March — and employers cut a stunning 21 million or more jobs in April, economists have forecast, according to data provider FactSet. If so, it would mean that nearly all the job growth in the 11 years since the Great Recession had vanished in a single month.

Many people still employed have had their hours reduced. Others have suffered pay cuts. Some who’ve lost jobs won’t have been able to look for work amid widespread shutdowns and won’t even be counted as unemployed. A broader measure — the proportion of adults with jobs — could plunge to a record low.

The government will issue the April jobs report on Friday morning. On Thursday, it will release the latest weekly report on applications for unemployment benefits. It will likely show that about 3.5 million people sought jobless aid last week. That would bring the total number of layoffs to nearly 34 million since the shutdowns began seven weeks ago.

That figure is much larger than the expected April job loss because the two are measured differently: The government calculates job losses by surveying businesses and households. It’s a net figure that also counts the hiring that some companies have done despite the widespread layoffs. By contrast, the total jobless claims is a cumulative figure that includes aid applications begun in March.