The ground remembers every storm.

On August 29, 2005, Hurricane Katrina pushed the sea onto the Mississippi coast. A damage survey by Haag Engineering measured the highest still water at 9.7 meters, about 31 feet, inside a school on Coleman Road in Waveland, just east of where the eye crossed. In low-lying Bay St. Louis and on Biloxi’s Langley Point, waves stripped whole neighborhoods to what the surveyors called “slick” slabs. Across the slab foundations they examined, the house frames were usually gone, and some of the slabs themselves had broken up or collapsed.

Thirteen years later Hurricane Michael came ashore at Mexico Beach, Florida as a Category 5. Engineers led by Andrew Kennedy measured high water marks of 7.2 meters, roughly 23.6 feet. Wave and surge damage was nearly total for low-lying properties, many of them “destroyed down to the foundations.” Damage dropped sharply as elevation rose. Much of the worst damage was in FEMA X zones, outside the mapped 100-year floodplain.

In September 2022 Hurricane Ian made landfall near Fort Myers as a Category 4 with 150 mph winds and up to 12 feet of surge. A Geotechnical Extreme Events Reconnaissance team sent in afterward documented high levels of scour and erosion at coastal sites and varying degrees of foundation performance.

In late June 2012, Tropical Storm Debby stalled over Florida and kept raining. In Hernando County, north of Tampa, officials logged 56 reports in the days after, many describing more than one hole. By early July the count was nearly 200 sinkholes in that county alone.

The geology had been waiting. The Southwest Florida Water Management District describes how rain and groundwater slowly dissolve the limestone under the state, and how the sand and clay above can bridge a cavity for years. Heavy rain is one of the triggers it lists. The rock prepared the hole over thousands of years. The storm decided the date.

The drought that began in the fall of 2010 produced the driest year in Texas’s recorded history. In 2011 the state averaged only 14.8 inches of rain, setting records for low rainfall from March through May and again from June through August.

Much of Texas sits on clay that swells when it is wet and shrinks hard when it dries. The Texas state soil, Houston Black, is one of them. When a drought like 2011 pulls the water out, the clay contracts, the perimeter of a slab loses support, and the house settles at its edges. Then the rain comes back and the clay swells again. A foundation on that ground spends its life riding the cycle.

In January 2010 a hard freeze settled over the strawberry fields around Dover and Plant City, east of Tampa. Growers protect the berries by spraying them with water, which releases heat as it freezes. Over the course of the freeze, that pumping dropped the aquifer about 60 feet. Almost 140 sinkhole complaints followed, along with more than 750 complaints of dry wells, according to the Southwest Florida Water Management District, which later created a water use caution area for the region.

Along the Texas coast, the same physics works over decades. When groundwater is pumped from the sands under Houston and Galveston, the clay layers between them compact and the land goes down. The Harris-Galveston Subsidence District’s maps show as much as 10 to 11 feet of subsidence in parts of the two counties between 1906 and 2016. It took a hurricane to make people look: after Hurricane Carla’s surge and flooding in 1961, local governments began studying what subsidence was costing them, and in 1975 the Legislature created the district to regulate pumping.

In Arizona, pumping has lowered whole desert basins and torn open earth fissures. Near Eloy the land dropped 15.4 feet between 1952 and 1985.

On October 17, 1989, the Loma Prieta earthquake shook the San Francisco Bay Area. Some of the worst damage in San Francisco was in the Marina District, a neighborhood built on sandy artificial fill. According to the U.S. Geological Survey, the soft soils there amplified the shaking to damaging levels, and the fill liquefied. The water system in the Marina needed 123 pipeline repairs, more than three times as many as anywhere else in the city’s system. Crews replaced about 13.6 kilometers of gas lines.

The USGS defines liquefaction simply: loosely packed, water-logged sediments at or near the surface lose their strength in strong shaking. Buildings on that ground tilt, settle and crack, even when the structure above was built to code.