Police in Chelan County, Wash., discovered some 20,000 marijuana plants with a potential value of $30 million growing in national forest lands -- and authorities say they have found just 20 percent of the pot crop planted in the county.
Chelan County Sheriff Mike Harum said the massive fields appear to be part of an organized growing effort by groups from either California or Mexico.
The people planting the fields walk two to three miles back into the woods carrying small marijuana plants in egg cartons, and then set up camp and tend the plants for about three months.
It would seem that so many pot plants growing in the woods would be easy to spot, but when a reporter from ABC News affiliate KOMO-TV in Seattle took an aerial trip over the area with the sheriff, he found the plants were nearly impossible to spot from the air.
But Harum said that when the sun hits them just right, they shimmer and they stand out from the surrounding forrest because of their emerald green color.
The marijuana plants are planted on huge tracts underneath evergreen trees and vine maples. Workers bring plastic hose and tubing with them, then they dam up small streams and construct irrigation systems so they can care for the pot plants.
Harum said the marijuana being grown in the Washington forest land is of extremely high quality with a THC content of 30 percent.
The problem has been growing for the past three or four years, and it is not just in the Washington woods. Local police and federal drug enforcement agents and park rangers up and down the West Coast have been finding more and more sophisticated pot fields in national and and state parks and forests.
Harum said he doesn't know if the marijuana cultivation was started after the United States clamped down on traffic across the Canadian border following the terror attacks of Sept. 11, 2001.
But a local woodsman, Brett McGinnis, told KOMO-TV that he has hiked in the woods of Chelan County for more than 20 years and he did not see marijuana until the past three or four years.
The sheriff's office has made only one arrest, taking into custody a California man. There are indications that some of those people who hauled in the material to set up the grow were transported from Mexico, just for the purpose of putting it in, Harum said.
That is a pattern that police have seen in other areas in the West where large-scale pot grows have been found in recent years. Federal and local police have told ABCNews.com that they regularly find food, newspapers and other materials at the grows they raid that indicate the people working there were Mexicans.
Chelan County Chief Criminal Deputy Sheriff Clyde Foreman told KOMO-TV police have no idea where the people who had manned the grows they found disappeared to or what state they're in. He said some of the workers are told: "If you don't do this, we'll kill your family."
But if the work comes with threats and the danger of arrest, it also can bring in a lot of money. Foreman said some workers are believed to be paid up to $400 a day to tend the marijuana plants.
The DEA, FBI, and the Chelan County Sheriff's office told KOMO 4 News they are continuing to fly the area searching for additional grow operations.