Here is the opening statement from the Department of Labor:

COVID-19 Impact
During the week ending March 21, the increase in initial claims are due to the impacts of the COVID-19 virus. Nearly every state providing comments cited the COVID-19 virus impacts. States continued to cite services industries broadly, particularly accommodation and food services. Additional industries heavily cited for the increases included the health care and social assistance, arts, entertainment and recreation, transportation and warehousing, and manufacturing industries.

In the week ending March 21, the advance figure for seasonally adjusted initial claims was 3,283,000, an increase of 3,001,000 from the previous week's revised level. This marks the highest level of seasonally adjusted initial claims in the history of the seasonally adjusted series. The previous high was 695,000 in October of 1982. The previous week's level was revised up by 1,000 from 281,000 to 282,000. The 4-week moving average was 998,250, an increase of 765,750 from the previous week's revised average. The previous week's average was revised up by 250 from 232,250 to 232,500. [See full report]

This morning's seasonally adjusted 3.28 million new claims, up 3M from the previous week's revised figure, was worse than the forecast of 1.65M.

Here is a close look at the data over the decade (with a callout for the past year), which gives a clearer sense of the overall trend in relation to the last recession.

Unemployment Claims since 2007

As we can see, there's a good bit of volatility in this indicator, which is why the 4-week moving average (the highlighted number) is a more useful number than the weekly data. Here is the complete data series.

Unemployment Claims

The headline Unemployment Insurance data is seasonally adjusted. What does the non-seasonally adjusted data look like? See the chart below, which clearly shows the extreme volatility of the non-adjusted data (the red dots). The 4-week MA gives an indication of the recurring pattern of seasonal change (note, for example, those regular January spikes).