Bernie Sanders had a good weekend in the Alaska, Hawaii, and Washington State Caucuses. He beat Hillary Clinton with over 70% of the vote in all three States. As things stand, Sanders needs to win 2/3 of the remaining delegates. He won more than that share yesterday. While exact delegate counts are still being sorted, Sanders probably won around 120 delegates to Clinton's 50.
Sanders has always done better in closed caucuses, where independents cannot vote and where participation typically takes a commitment of several hours. As a result, voters tend to be more hard core and hold more extreme views than the public in general. Still, victories of 70% or 80% are very impressive.
The wins were more than enough to keep the Sanders Campaign going, with an infusion of money and support.
The next contest is an open primary in Wisconsin in about a week and a half. Clinton and Sanders are virtually tied there in the polls. But after Wisconsin comes a number of mid-Atlantic States, including Pennsylvania and New York, where Clinton has roughly 30 point leads in the polls. If Clinton does as well as the polls suggests, even Sanders' landslide victories in these smaller caucuses will not be enough allow hit to catch Clinton in delegates.
Sanders could possibly continue to win the remaining States without the necessary margins to catch Clinton, but because he had so many wins, many Superdelegates who have pledged support to Clinton could switch there votes. Superdelegates do not want to be in the uncomfortable position of nominating a candidate who does not win the most delegates in the primaries. Still, that remains a long shot strategy for Sanders as well.
Sanders has momentum after yesterday's wins. But keeping up that pace in the States ahead does not seem likely given the polling in those States.