When Yahoo (YHOO) CEO Carol Bartz got fired yesterday afternoon, via chairman Roy Bostock’s phone call to her cell, and when Bank of America’s (BAC) Sallie Krawcheck got booted by her CEO, Brian Moynihan, two of Fortune’s Most Powerful Women hit the wall.

In a way the two women are extremely different.  Bartz, who took charge at Yahoo in TK, after a successful run heading Autodesk (TK), was No. TK on our list but sliding lower, as she struggled to lift Yahoo’s ad sales vs. an ever-growing Facebook and Google (GOOG). Krawcheck, who started out on our MPW list as one of the youngest stars–when she was CFO of Citigroup at age TK–was No. TK on last year’s list and likely to hold her rank this year  because, by all accounts, she was doind a good job at a beleaguered company.

As we at Fortune rank women leaders across the business universe for the 2011 Most Powerful Women list, to be released three weeks from now, we suddently have two empty slots.

technology broad, startled everyone with her candor when she busted into the industry. Threw up on the lawn her first week at Autodesk, recruited by Yahoo and never settled in. Said Fuck you…Interviewed her in December, asked what grade, Pass. Lunch in June, she was uncomfortable about her position, predicting the end of her line.

Sallie put herself out there in the media gaze. Twice on the cover of Fortune…the last honest analyst whom Sandy Weill recruited to help clean up Citigroup, got pushed out of her job there for fighting for her clients—she was proud of that. Always drama with Sallie, as with Carol. Hilarious story about the job she almost took. She’s tough. Friend who had a meal with her recently said she seemed to be feeling fine despite the storm at BofA.