Thunder & Lightning Policy

Please be aware that it is the policy of the Atkinson Pool and the Town of Sudbury, with the safety of our members and guests in mind, to evacuate the pool during a thunder & lightning storm.

There are some 22 million cloud-to-ground lightning flashes in the USA annually. Lightning travels at about 1000 feet in a millionth of a second. A typical flash is as thick as one’s thumb. Lightning’s currents average about 25,000 amps with voltages in the hundreds of millions. Lightning follows Benjamin Franklin’s maxim of Path of Least Resistance through the air and along or through the ground. According to insurance information, the ratio of damage due to indirect effects vs. direct effects is a ratio of some 2000:1. This means that if lightning strikes the ground near to an indoor pool, depending upon localized circumstances, it may be conducted into the building via low resistance conductors. These can be:

• Buried or pole-mounted telephone and electric wires
• Buried metal water lines or gas lines
• Metal light masts in parking lots with AC power fed from the building
• Fences that are contiguous to the building
• Cable TV lines, both aerial and buried
• Root systems of nearby trees
• Wet ground and wet paved parking lots (from rain) adjacent to buildings

While no reported human injuries have occurred in indoor swimming pools, it is the recommendation of the National Lightning Safety Institute to remove swimmers from indoor pools and shower areas during severe storms. There are multiple reported cases of mechanical damage to equipment located inside buildings that suffer a near ground or building strike.

The pool will be cleared and will not re-open until 20 minutes have passed from the last thunder boom, or visible lightning. If you purchased a daily pass, and the pool was cleared, please stop by the front desk to pick up a lightning pass entitling you to another visit to the pool.

Thank you for your cooperation,

Atkinson Pool Staff