BROWNSVILLE - With parts of the Rio Grande Valley under a freeze warning Tuesday night, below freezing temperatures can be deadly for citrus.

Most of the industry is still recovering from a freeze over 30 years ago. Just the word “freeze” is enough to put growers on edge.

"It just puts us out of business. We don't recover our production for three, four years afterwards," said Fred Karle a citrus grower in the Valley.

Karle is no stranger to the devastation a freeze can bring to citrus. The most recent significant one happened in 2011.

"The trees just got iced over and there again we couldn't tell that there was real damage to them," said Karle.

Geoffrey Bogorav, a senior meteorologist at the National Weather Service in Brownsville, explained what happened that year.

"We had an ice storm at that time we did have an upper-level disturbance that brought in freezing drizzle and rain," he said.

The National Weather Service office in Brownsville keeps track of all freeze events across the Valley.

"Not all freezes here in the Valley mean there’s going to be snow or ice it's usually just temperatures dropping to 32 degrees or below," said Bogorav.

For the lower Valley temperatures dropped to 32 degrees or under every two out of three years. For the mid-Valley, it's three out of five years. For the upper Valley and ranchlands, it’s nine out of 10 years.

Karle says he's been able to handle most these freezes over the years except for two which nearly cost him his entire business.

"You could almost hear too, trunks splitting from the cold," said Karle.

Both were in the ‘80s.

"Those were major arctic outbreaks in ‘83 and ‘89 in which major temperatures dropped below 20 degrees," said Bogorav.

In '89, temperatures were below freezing for over a day. Ice crystals formed inside grapefruit and thousands of acres of citrus trees were destroyed.

"We were froze before we knew it," said Karle.

According to Texas Citrus Mutual, before both freezes, there were about 69,000 acres of citrus in the Valley. After the freezes, it’s down to around 20,000.

Karle himself lost several hundred acres.

"Some of them were sold for development. Some of the leased ones the owners decided to doze them out so we didn't have anything there,” he said.

Since then, the industry is still recovering. Currently, there are about 27,000 acres of citrus groves across the Valley. This is less than half of where it was over 35 years ago.

"It's like losing an old friend and losing your job and everything else it was very depressing we were taken by surprise," said Karle.

While Karle does not feel conditions this week will be nearly as bad as in the past, he's keeping an eye out and hoping for the best.

Karle says when temperatures drop to 26 degrees for several hours, that’s when he begins to really worry.

He says that's when you can start to see damage to both the fruit and trees.