SACRAMENTO (CBS13) — A big holiday weekend full of sunshine will have many families hitting the water for the first time this season. It’s fun but will be fairly dangerous as the fifth-largest snowpack in state history starts to melt.

Officials said currents along the Sacramento River are moving at 4-5 knots on top and double underneath. Additionally, rafting spots such as the American River have more rocks and are filled with runoff-debris including fallen tree limbs.

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Experts are warning families that before they go on the river, make sure you know what you’re doing, or find someone who does.

Guy Cables has been working in the outdoor adventure industry for four decades. He has seen a lot of snow melt in his time with Sierra Outdoor Center in Auburn, and this year will be one of the most exciting.

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“Already flows are double, triple, what you see this time of year and we haven’t really had any melt yet,” Cables said.

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He said the south fork of the American River is a popular spot. Others are more difficult to maneuver and normally require a commercial outfitter to guide you.

“You may not die, but you will flip and swim and when flows are high, there are no eddies so you will be in the water longer and you want to be dressed properly,“ Cables said.

Experts say the water can be enticing on a hot spring day but be careful and don’t let your guard down. The cold water from the snowmelt will catch swimmers off-guard and can be very dangerous.

“It’s liquid snow you got about two minutes to get out or your body locks up and you drown,” Cables said.

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Officials suggest you always wear a life jacket when going into the water.