It looks like the initial strikes during the first 24 hours were carried out primarily by sea, ground, and air launched cruise missiles. With the Iranian air defenses significantly degraded, the B-2's were apparently on the prowl last night with primary targets being the Iranian missile storage facilities. They do not need the heavy penetrators needed for the nuclear sites to close or destroy these stockpiles. Normal 1k and 2k penetrators would reach most of them, and as the article suggests, pulling the mountain down over the entrance takes them off the table for this campaign. More are likely there right now.
As a by the way, it is ridiculous we only have twenty of these. George H. W. Bush curtailed production in the early nineties from 132 to 20 because we would never have a need for them with the collapse of the Soviet Union.
Its replacement is the the B-21 and is just entering low rate production. Though similar in appearance, it is as revolutionary as its predecessor. We'll see if it survives the next administration.
The arrival of the B-2s marks a change in the air campaign and will put certain target sets at greater risk as the operation expands.
www.twz.com