Extreme weather has once again caught the US military off guard.

At Offutt Air Force Base in Nebraska, headquarters of US Strategic Command and home to more than 10,000 personnel, floodwaters reached up to 7 feet deep on Friday and forced one-third of the base to relocate offices. The flooding also forced the base to cancel an airshow scheduled for June.

“The speed at which it came in was shocking,” Col. David Norton, who manages facilities at Offutt Air Force Base, told the Associated Press.

Nebraska is just one of several states in the Midwest experiencing severe flooding this month following a wet winter, a rapid spring thaw, and a “bomb cyclone” storm that dumped huge amounts of rain and snow into already full waterways like the Mississippi and Missouri rivers.

The flooding has claimed several lives and caused billions of dollars in damages. And forecasters expect that the situation will only get worse later this spring as an “unprecedented” flood season takes hold.

Global warming is a major factor in the above-average precipitation in recent extreme rainfall events, since warmer air can hold on to more moisture than cooler air. And scientists project that climate change will increase the volatility in weather, with rapid switches between drought and deluge and heat and cold in some parts of the country. The recent winter snowfall and rapid thaw certainly fit that pattern.

The US military has long recognized that climate change poses a strategic risk as it drives migration and acts as an ingredient in conflicts around the world. It also poses a more immediate risk to critical facilities like naval bases. But the recent storms also show that there is a wide gulf between acknowledging a risk and being positioned to cope with it.

As NBC News and InsideClimate News reported last week, officials were well aware the base was at risk. Another flood came alarmingly close to the base’s runway in 2011, and in response, base officials and local planners investigated flood risks as part of a land use study published in 2015.

The study noted that existing infrastructure wasn’t enough to cope with growing flood concerns due to climate change:

Due to changes in the base flood elevation of the Missouri River, Federal Emergency Management Agency (FEMA) has identified the need to raise the levee between two inches to several feet for it to be capable of protecting the installation. The Papio‐Missouri River Natural Resources District (P‐MR NRD) has been notified by FEMA, that if the levee is not fixed by 2017, the levee will be de‐certified.

However, the process of raising levees to protect against flooding dragged on and was still not completed by the time the recent storms struck the region, leaving the base vulnerable to rising water.

Other military installations were also impacted by the recent floods. The South Dakota Air National Guard had to relocate some of its F-16 fighter jets, and several installations are now staging supplies and workers for disaster relief.

And last year, Hurricane Michael damaged Tyndall Air Force Base. Several F-22 aircraft, the Air Force’s most advanced and most expensive fighter jet, were stuck in harm’s way as the storm rapidly intensified.

These are examples of the climate risks faced by a massive global operation like the US military, which manages hundreds of thousands of personnel, billions of dollars in materiel, and thousands of acres of land. And with such a large footprint, there are lots of potential vulnerabilities.

Though President Trump, the commander-in-chief, has repeatedly dismissed the threat posed by climate change, the US military and the intelligence officials have been surprisingly clear-eyed about the problem. Director of National Intelligence Dan Coats described climate change as a national security threat for the second year in a row in his Worldwide Threat Assessment report.

Pentagon officials have been raising the alarm about climate risks to military installations and have frequently framed climate change as a threat multiplier.

However, a vast institution like the US military takes a long time to adapt. Even when they see what’s coming, they can’t be ready in time. Many military bases are decades old and span vast areas, making them hard to protect. Relocating thousands of service members is costly and time-consuming. And even the most agile aircraft have huge logistical demands that make it difficult to quickly evacuate should a storm come over the horizon.

It’s a tough lesson for everyone else trying to get ahead of the rising sea levels, increasing wildfire risk, more extreme storms, and hotter temperatures already unfolding because of climate change. We can sit back or start adapting to a “new normal” of constant change. The choice is ours.