The phrase "sparse crowd" means that there are only a few people gathered in a particular place, and it is not crowded or packed with people. Full definition
About a third of the already sparse crowd got up and left, never to return. (slickstermagazine.com)
Unlike in Canada, where the country's biggest universities play in front of sparse crowds and go years without winning a season, U.S. colleges outside of the Ivy League depend upon their sports teams to bring in new students, attract attention, and draw donations and revenue. (canadianbusiness.com)
It's then that you'll get the optimal combination of pleasant weather and relatively sparse crowds on the trails and at the citadel itself. (businessinsider.com)