Illegal immigration across the southwest border surged 200 percent in March compared to the same month last year, according to Homeland Security statistics released late Wednesday that back up White House’s claims that things are quickly deteriorating on the border.

The year-over-year surge is by far the largest in the records, which date back to 2011, and it could be a signal that the Senate’s debate on legalizing illegal immigrants earlier this year has sparked a new wave of migration.

The Border Patrol and officers at the ports of entry nabbed 50,308 people in March — up from less than 37,000 in February, and three times the 16,588 people apprehended in March 2017, when President Trump’s tough enforcement talk had sparked a major drop in illegal immigration attempts.

That drop only lasted a few months and since last summer the numbers have been steadily increasing again, reaching back to levels not seen since the middle of the illegal immigration surge during the Obama administration.

The numbers were released just as Mr. Trump was signing an order deploying National Guard troops to the southwest border to assist in enforcement. The government couldn’t yet say how many troops were being sent, what their duties would be, nor how much it would cost — though Homeland Security Secretary Kirstjen Nielsen said they could be deployed as early as Wednesday night.

According to the new numbers, the Border Patrol caught 37,393 illegal immigrants in March. Customs and Border Protection Officers, who man the ports of entry, encountered another 12,915 people who showed up without permission to enter.

Those numbers are considered a rough yardstick for the overall flow of illegal traffic, so increases in the number of people caught signals an increase in overall illegal immigration.

Analysts say that migration is seasonal, so comparisons to the same time in previous years gives the best sense for where things are headed.

Particularly troubling for officials was a major jump in the number of illegal immigrants traveling as families. Nearly 9,000 were nabbed by the Border Patrol and another 5,100 were stopped at ports of entry. By contrast, in March 2017 the Border Patrol caught just 1,125 immigrants traveling as families, and the officers at the ports of entry stopped just 768.