Busy holiday weekend keeps emergency services hopping as heat, humidity jump Police officers, lifeguards and paramedics got their first true test of the summer months with a huge influx of visitors to local beaches during the long Fourth of July holiday weekend. An estimated 1.12 million people flocked to the beaches and Mission Bay to enjoy the higher weekend temperatures and seek some relief from humid monsoonal conditions. Lifeguard officials reported 738 water rescues over the three-day holiday — more than three times the number of rescues made in 2009 and 2010. Medical aids also increased by more than twice the 2010 numbers for the same period. The busiest of the local beaches was Mission Beach, with about 160,000 people. One diver died off Mission Beach on Saturday during an apparent diving accident and law enforcement officials reported a jump in the number of drunken-driving arrests and fatalities over figures for last year at this time.