The Memorial Day holiday weekend, something of a traditional start of the good-weasther season, should also be a time when people think twice before dipping into the dangerously cold waters in this area.

That’s the message from local safety officials, who already are dealing with worst-case scenarios.

Each year, King County residents die when they venture into waters without appropriate lifesaving gear and lifeguard protection, officials warned. In late spring, even as the weather warms up, lakes, rivers and Puget Sound are still extremely cold. Melting snowpack feeds rivers that are running deep, cold and swift.

The Seattle-King County Public Health Department urges water enthusiasts to use extreme precaution in their activities.

“No matter what the outside temperature reads, late spring is not a good time to be swimming in local rivers, lakes or in the Sound,” said Dr. David Fleming, the department’s director . “Even the best swimmers with lifejackets are at risk for serious trouble in the cold water.”

Last year, 24 unintentional drowning deaths occurred in King County. Fifteen of those happened in rivers, lakes or Puget Sound. And six of them – 25 percent of the 2007 total – took place during the months of May and June, officials said.

The Green River proved to be a dangerous place for people looking to get out of the record high temperatures last Saturda. Emergency personnel rescued nine people and had lengthy searches for two more.

In one incident, a kayaker disappeared after hitting a rock. Other kayakers searched for him for about 30 minutes. Search teams from several agencies continued the search.

Another man disappeared when four men were thrown into the water near Flaming Geyser State Park. The mishap occurred as a pair of small inflatable rafts that were tied together flipped. Three of the men were rescued.

Mountain View Fire and Rescue participated in the searches. Other agencies that were involved in searches and emergency medical care included the King County Sheriff Department, Washington State Parks, Rescue One, Renton Fire Department, Valley Regional Fire Authority and Medic One.

Tim Perciful, a spokesman for Mountain View Fire and Rescue, provided this account:

“Once on scene, we found two people stranded on two separate islands within the park. It also came to our attention that there were six other people stranded on an island downstream. (Mountain View personnel) launched a rescue raft to help the two people within the park.

“The two people rescued were part of a group of four that launched two inflatable rafts in the park. They had the two rafts tied together and had their hands strapped to the rafts since they were not wearing life jackets. One of the other members from the party was able to get out of the river on his own.

“Within five minutes of the two rescues, we heard a man yelling from one of the same islands that we had previously rescued a man. Mountain View sent the rescue raft out again to get the man off of the island.

“Other members of Mountain View Fire and Rescue, along with King County Sheriff, Rescue One and Guardian 2 (the Sheriff Department helicopter) found five people stranded on an island and one stuck on a log in the water downstream. The woman in the water was too cold to stand and had to be rescued by helicopter. She was then transported to the hospital for an evaluation. The other five people were taken off the island with the help of rescue personnel.”

Perciful noted the river “is extremely dangerous due to fast, high and cold water. This combination can make a fun day in the water into a deadly venture within a moment.”

The fast-flowing river can flip boats and pin people beneath rocks or logs.

“We hope that people will stay out of the water,” Perciful said.

Lakes and rivers are particularly dangerous before summer. Beaches don’t have lifeguards yet and rivers are colder, swifter and more hazardous than later in the summer.

“River systems aren’t only extremely cold this time of year, they are constantly changing and may have new pieces of wood either submerged or spanning river channels that can present serious dangers,” said Theresa Jennings, director county’s Department of Natural Resources and Parks. “Rivers will be running high and swift from snowmelt. Swimming is not a good idea in these conditions, and people should exercise great caution when navigating or doing recreational activities on the river.”

Kayakers, rafters and other boaters should stay away from rivers unless they are highly experienced, or should sign up with professional touring companies. Officials noted that professionals will know the river and be aware of common locations where treacherous logjams are located at this time of year.

In addition, children should never be on a river without the close supervision of an adult, officials said.

According to the Health Department, safety guidelines include:

• Be trained in rescue skills, CPR and first aid, especially for recognizing and treating hypothermia.

• Be a competent swimmer.

• Know how to handle your water craft with the proper use of paddles and oars.

• Always stay alert for unexpected hazards.