Haleakala National Park is seeing an unusually high number of Western yellowjacket wasps, and park officials are warning visitors to take necessary safety precautions.

Wasp numbers typically peak in the summer months, but "the numbers are going up in places that visitors frequent," said park biologist Raina Kaholoaa.

"As with everything else in nature, sometimes you have higher numbers than others," said Kaholoaa. "This year, numbers are exceptionally high."

The park will remain open as resource managers try to control wasp populations.

High wasp numbers have been reported at the Kapalaoa Cabin, the base of the Sliding Sands trail and at the trail junction to the Halemau'u Trail.

Those who are allergic to wasp and bee stings are being asked to avoid those areas and to carry prescription medications, Kaholoaa said.

"We don't want to discourage visitors from coming, but we want to warn visitors that there is a possibility you can get stung," she said. "There are things we can do such as not wearing scented perfumes, which attract the wasps."

Wasps are also attracted to water, meat, sunscreen and sweets, according to a park news release. They may swarm around people who are stopping for a snack, and may sting repetitively.

Stings may cause redness, swelling and itching. Severe reactions include difficulty breathing, hives, loss of consciousness, anaphylactic shock and respiratory arrest.

Park officials are urging people to avoid problem areas and to remain calm in the event that a wasp attacks. Swatting at the wasps will only make them more aggressive, according to the release. Visitors are advised to walk calmly away from the swarm and to notify park staff in the case of a medical emergency. If a serious reaction occurs, visitors should call 911.