Yesterday’s stunning claim by the Yemeni Houthi forces that they had killed hundreds and captured thousands of Saudi troops in a surprise attack inside Saudi Arabia was seemingly backed up by the release of Houthi video showing destroyed Saudi military vehicles and some troops surrendering. As of this writing, the Saudi government has not commented, which may indicate that the claims are true.
The Houthis say they affected this win with missile and drone attacks on Saudi positions. In the ongoing Yemen War, the Houthis have made cross-border raids before, but nothing on the scale of what they are now claiming. If true, this is a major escalation of the ground war, and brings to question what role the Iranians may have played in helping the Houthis. While the Saudis and their allies (in particular the Americans), prefer to believe that the Houthis cannot fight at a sophisticated level (such as would be required for the precision air attacks on the Saudi oil facilities two weeks ago), if we compare the current state of Houthi military capability to that of another Iranian client, Hezbollah in Lebanon, no one would doubt the military effectiveness of Hezbollah in 2019.
It may be entirely possible that through years of combat and Iranian training and support, the Houthi really are a fully capable military force that can do real damage to their Saudi enemies.
Below is a video from al-Jazeera that shows what the Houthi claim are destroyed Saudi armored vehicles and Saudi troops surrendering.
The attached map shows the international border between Yemen and Saudi Arabia and the location of Najran, the site of the battle. The green border shows approximately the territory under Houthi control in 2019 inside Yemen. This map was adapted from a Google Maps view of the Yemen-Saudi border.