How vulnerable is Saudi Arabia to Houthi missile and drone attacks?

As the crisis between Iran and the US heats up, Iranian-backed Houthi rebels in Yemen have intensified their missile and drone attacks on Saudi Arabia. Such attacks are in retaliation for the Saudi-led coalition intervention in Yemen, and demonstrate clearly the growing military capabilities of Yemeni fighters and the weaknesses in Saudi Arabia’s air defences.

In the past three months, Houthis have targeted strategic Saudi infrastructure including airports, a desalinisation plant, oil pipelines and major cities. One of the most serious attacks occurred in mid-June when the civil airport in Abha was hit; 26 people were injured. The increased frequency of attacks on targets all over Saudi Arabia as well as the UAE reflects the technological advancement of Houthi forces, primarily in terms of greater sophistication and range. With powerful missile systems at their disposal, Houthis are proving to be a formidable force, capable of inflicting a lot of damage on their foes.

According to Missile Defence Advocacy Alliance (MDAA) data, the Houthis most likely acquired the Scud-B and C missiles, the North Korean Hwasong variants and the Tochka missile from the ousted Yemen government. The Qaher-1 missile, the Zelzal-3 ballistic missile and the C-802 anti-ship cruise missile were delivered later, during the ongoing conflict. The US and Saudis believe that Iran, Russia and Lebanon’s Hezbollah have been the main suppliers of these systems.

READ: Houthi drone attack on Saudi Arabia’s Abha Airport leaves nine injured 

When it comes to drones, an expert on emerging military technologies and humanitarian disarmament project leader for the Dutch peace organisation PAX said that current information on the type of drones shot down or otherwise found teaches us that they are based on Iranian versions. Wim Zwijnenburg added that the adapted version has been assembled in Yemen, either with home-produced or imported materials, including the loitering munition version. Reports from UN Security Council experts show that both the range and payload of the so-called “suicide/kamikaze drones” have increased, making them more effective. UN experts have estimated, for instance, that drones used by the Houthis have a range of over 1,000 kilometres, allowing them to penetrate deep into Saudi territory.

Justin Bronk, a research fellow at Britain’s Royal United Service Institute for defence and security studies (RUSI), said that if drones approach close enough to key personnel, they can pose a significant security threat to Saudi Arabia, although in terms of the damage that they can inflict on facilities they are very limited. “The size of warhead that they can carry is much smaller than that found even on a single missile,” Bronk pointed out. “They are very useful for nuisance attacks and to highlight that Saudi defences cannot cover the whole of their territory but are not a critical physical threat.” Hence, as the payload of a single drone is limited, it would require swarm attacks of smaller drones to create a major impact.

Any escalation of the US-Iran conflict will only intensify these attacks on Saudi Arabia and its allies, and possibly on US military targets in the region, showing how effectively Iranians can use proxies to hurt their enemies through ever more accessible and sophisticated military technology. Zwijnenburg said that the important lesson we are learning from these incidents is that both state and non-state actors are utilising the deployment of various type of armed drones to boost their military capabilities. “We are likely to see more use of small and medium-sized armed drones and kamikaze drones,” he told me, “in particular swarming technology, as this can overwhelm enemy defences and drones are getting cheaper to produce.”

Since 2014, the Saudi authorities have reported well over a hundred Houthi missile attacks. While many of these have been intercepted, the Saudi armed forces have been unable to block them all. Despite huge spending on military hardware and technology, the recent attacks expose gaps in Saudi Arabia’s air defences and also ask questions about the effectiveness of the naval blockade of Yemen; the Houthis have obviously been able to acquire sophisticated equipment despite the blockade.

READ: US calls on Houthis to end attacks on Saudi Arabia. 

According to Bronk, drone and missile attacks are almost certainly enabled by Iranian support in terms of missiles, drone components and explosives. “Since the drones being used are relatively small,” he explained, “the component parts are much easier to smuggle through the blockade than missiles are.”

Furthermore, noted Zwijnenburg, Saudi Arabia has a long border with Yemen and many vulnerable targets. “Considering the small radar signature of drones, it makes them hard, but not impossible, to spot and intercept.”

The Saudis rely heavily on Western, mostly American, air-defence systems, so Houthi drone and missile attacks throw the spotlight on their weaknesses. Videos from last year, when Houthis fired Scud ballistic missiles towards Riyadh, for example, exposed a serious malfunction in the US Patriot missile system which, in short, missed the targets that it was supposed to intercept.

Bronk explained that modern air defence systems such as the Patriot PAC-3, THAAD or S-400 are not really very good at engaging small drones. Their radars are calibrated to track extremely fast objects, specifically ballistic missiles, cruise missiles and combat aircraft; they are not optimised for tracking small, slow-moving objects such as loitering munition or converted hobby-type drones. “Even when these small drones can be tracked,” he added, “firing large ballistic missile defence interceptor missiles which cost millions of dollars each is not a sustainable practice.”

Hence, Zwijnenburg suggests that other approaches would be more effective. Electronic warfare, perhaps, or smaller versions of air defence systems which use lasers or short-range surface-to-air missiles.

The ongoing Houthi missile and drone attacks on Saudi Arabia, therefore, suggest that a US-led war with Iran could have devastating consequences for Saudi Arabia and other allies, especially if Iran unleashes its proxies in the region.

The views expressed in this article belong to the author and do not necessarily reflect the editorial policy of Middle East Monitor.