Yahoo TV

STORY: Two barriers demarcate the U.S.-Mexico border here between San Diego and Tijuana.

Meant to deter illegal border-crossings, aspiring migrants have tried to scale these walls.

Some slip, and do not survive. Those who do may suffer severe injuries, and frequently wind up here: San Diego's Scripps Mercy Hospital.

Dr. Vishal Bansal is the chief of trauma surgery, and he's seeing more and more of these patients.

"So we've seen a massive uptick in the number of patients from the end of 2021 up until now. It's been a constant stream. It's getting more and more. We trade border call with UCSD. So on the odd months, we take the border patients, on the even months UCSD takes border patients. So currently for us, we're definitely seeing an uptick compared to April. But if you look at the last year and a half, the slope has gone straight up in the air."

"This mass migration issue is this group of people coming over here, they're not told how bad it can really be.

Brent Schwerdtfeger is the chief of operations for the U.S. Customs and Border Patrol's San Diego sector.

He told Reuters the migrant deaths are due to more than just a border wall.

"It's not just coming off of a piece of infrastructure. It's coming across the harsh terrain. They could fall anywhere in the mountainous terrains that we have across the southwest borders as well. Plus, we have the, you know, we have a lot of water issues where the rivers, they have cross the rivers. Those are always traumatic that we have there. So they have to come across that as well. So it's not just a piece of infrastructure that could cause not only a bad injury, but, you know, a fatality as well."

From the highways of San Antonio, Texas, where 53 migrants died last month after being packed into a sweltering tractor-trailer, to the unrelenting heat of the desert in Arizona, and the wall that former President Donald Trump touted as “just about unclimbable,” there have been more than 1,000 fatalities on the border since U.S. President Joe Biden took office in January 2021.

Last year was the deadliest for migrants crossing the border, with 728 fatalities recorded by the United Nations.

The U.N. has counted 340 more this year, tracking 2021’s grim record.

A record number of crossings, more than 1.7 million so far this fiscal year through June, have been fueled in part by an expulsion policy put in place by Trump, a Republican, that Biden, a Democrat, has been unable to end.

That policy allows border agents to quickly expel migrants across the border.

As a result, many simply cross again and again, often making increasingly risky choices to avoid detection.

The Arizona desert is a particularly deadly option. Many migrants are overcome by heat and dehydration, and, if they're lucky, are able to dial 9-1-1.

Jesus Vasavilbaso is a U.S. Border Patrol agent with the Tucson sector.

“The calls that we have received this year for fiscal year they’re up more than 25 percent compared to last year at the same time. We are receiving approximately 16 calls a day, every single day 911 calls.”

Data from Humane Borders show that last year, 225 deceased migrants were found along Arizona's border with Mexico, the most since the earliest record kept in 1981.