I am an avid golfer as well as superintendent. I understand that golfers are passionate about their playing time and having your course close unexpectedly is frustrating. However; unexpected events and unforeseen circumstances can occur at any given time, and the #1 consideration a golf course superintendent must have in these circumstances is safety. Safety is the top priority and must be at the forefront of any decisions that are made to close or delay opening on a golf course.
Some situations that may arise and warrant delay/closure consideration due to safety concerns are:
Lightning (golf clubs are perfect conductors), standing water (on course, cart paths, walking areas, etc; can cause multiple unsafe scenarios), overly wet conditions (this can present several slipping hazards for guests and employees), storm damage (wind, rain or hail damage to trees and other course features), and extreme frost or snow.
This is not an exhaustive list, obviously other situations can and do arise, however the forefront of consideration must always be safety.