SPOKANE, Wash. -- In a show of continued enthusiasm on the ground, Democratic presidential hopeful Bernie Sanders on Sunday drew more than 30,000 people to three rallies around Washington, a state key to his strategy for an improbable comeback against Hillary Clinton.

The senator from Vermont took the stage here 40 minutes late for his final event of the day, delayed by impromptu appearances before three separate overflow audiences that couldn’t fit into the room his campaign reserved at the convention center.

The scene was similar at earlier stops Sunday in Vancouver and in Seattle. In Seattle, Sanders addressed a crowd estimated at 5,500 people outside of an arena where he spoke to a crowd of more than 10,000 people inside the arena, offering his prescriptions to rebuild the middle class.

“Please come out Saturday morning,” Sanders implored one of his audiences here, referencing the start time of the Washington caucuses. “Bring your friends, your neighbors, your uncles, your aunts.”

Clinton has opened a wide lead in the delegate count that will determine the Democratic nomination, but Sanders insists that the states coming up in the second half of the calendar, including those in the West, should be more favorable to him.

The first test of that proposition comes Tuesday, when Arizona, Idaho and Utah hold nominating contests. On Saturday, Alaska and Hawaii join Washington state on the Democratic calendar.

Sanders would have to win about 58 percent of the delegates awarded in the remaining states to catch Clinton. That’s a tall order, but one that Sanders’s campaign argues is possible given the number of large states where voters have yet to weigh in.

Washington state, with its liberal, largely white electorate, is one state where Sanders will need to run up the score if he stands a chance of catching the former secretary of state.

Sanders has struggled in states with large African American populations, particularly those in the South, where Clinton’s appeal to black voters helped build her commanding lead.

There was no shortage of enthusiasm Sunday as Sanders zipped around the state on his chartered jet, addressing the series of boisterous rallies and overflow audiences. In Vancouver, several people who waited outside in the drizzle held a sign reading “Jesus Would Vote for Bernie,” offering one of the more colorful expressions of support Sanders saw.

The crowd at Key Arena in Seattle was so large that it became impossible for the Secret Service to provide security checks in time for the venue to fill.

Even after the program was delayed by more than half an hour, about half of the upper deck remained unfilled. Yet an estimated 5,500 people waited outside to hear a separate address by Sanders, and another 1,500 left before he spoke, according to estimates by an official with the venue.

It was after 10:30 p.m. PDT when Sanders wrapped up his final event of the day here. He has stops planned Monday in Idaho, Utah and Arizona.