As a freshman at Ouray School, Judah Preston discovered what it’s like to play in a high school state basketball tournament in front of a packed house, to feed off the crowd’s energy.

Last week, he found out, with the same stakes on the line, what it’s like to play in front of virtually no one.

High school basketball teams across all five classification in Colorado, including Ouray, competed in front of nearly empty arenas last weekend. Then, before champions could be crowned, they watched t...