Climate Risk at the MSA Level

The fastest-growing metropolitan areas in the United States are disproportionately concentrated in regions facing the most acute climate-related pressures. Sun Belt and Mountain West metros - Phoenix, Las Vegas, Houston, Miami, Tampa, Austin, Dallas, Charlotte, Jacksonville - have attracted millions of new residents and massive commercial and residential real estate investment over the past two decades. Many of these same metros are experiencing serious climate related disruptions, including flood frequency, and wildfire exposure, and long-term water supply constraints, resulting in higher utility, capex, and insurance costs.

Three of the first measurable climate change trends are explored in the charts and text below:

1. Property insurance premiums (2011–2025)
2. High-tide (nuisance) flooding frequency (2014–2025)
3. Lake Mead elevation (2000–2026; representative of the depletion of the Colorado River system - the primary water supply for approximately 40 million people in one of the country’s fastest-growing regions)

Homeowners Insurance Premiums by State (2011–2025)

Figure 1. Homeowners insurance premium index by state (2011 = 100). Solid lines through 2022 are actual NAIC HO-3 average premiums, re-keyed from primary sources in August 2026 (III historical table archives for 2011–2021; NAIC 2022 report, Table 4). Dashed lines in the shaded area are estimates: S&P Global Market Intelligence approved rate changes applied to the 2022 actuals (2023–2024 by state; 2025 national only). States exposed to wildfire (Colorado), hurricanes (Louisiana, Florida), and severe convective storms (Oklahoma, Nebraska) diverge sharply from the national average after roughly 2019–2020. Florida’s path is notable: roughly flat 2013–2019, then a steep three-year surge. Sources: NAIC via III table archives (2011–2021); NAIC Data for 2022 report (May 2025); S&P Global MI (2023–25).

Key Observations

High-Tide Flooding: Observed Station Trends (2014–2025)

Figure 2. Observed annual minor high-tide flood days at seven NOAA tide stations, 2014–2025 (calendar years, NOAA Derived Product API). High-tide flooding (also called “nuisance” or “sunny day” flooding) occurs when tides reach roughly 1–2 feet above the daily average high tide, causing road closures and property damage even without storms. Year-to-year variability is driven by ENSO cycles, storm activity, and lunar cycles; the underlying upward trend is driven by cumulative sea level rise. In the 2023–24 meteorological year, 34 U.S. stations tied or broke their records. Note: NOAA’s national minor-flood thresholds are conservative - municipal counts using lower local thresholds (e.g., Charleston’s) run higher. Source: NOAA CO-OPS Derived Product API and Annual High Tide Flooding Outlooks.

Key Observations

Context & Discussion

Charleston, SC

Charleston is among the most visible examples of accelerating high-tide flooding in the United States. Two measurement systems tell the same story at different scales. By NOAA’s conservative national minor-flood threshold, the Charleston tide station recorded 1 flood day in 2000, 10 in 2015, and 19 in 2023. By the city’s lower local flood threshold - the basis of an NCCOS-sponsored study - the peninsula flooded roughly 2 days per year in 1950, 25 days per year by 2014 (42 total hours), and 38 days in 2015.[4] A 2019 city vulnerability study found that 70% of all residential properties in Charleston are highly vulnerable to flooding and 80% of the city’s annual sales volume and jobs are highly vulnerable.[5] Half of Charleston’s total sea level rise in the past 100 years occurred in the last 20 years.[5] The city has hired its first Chief Resiliency Officer, installed 22 check valves and backflow preventers to replace failing gravity-based drainage, and updated its flooding strategy to plan for 2–3 feet of elevation increase for new infrastructure.[5]

Miami & Southeast Florida

The vast majority of the Miami metropolitan area sits below 10 feet of elevation. Even a 1-foot increase over the average high tide causes widespread flooding across the metro area.[6] Miami Beach has replaced its gravity-based drainage system with pump systems because the old systems cannot function during high tides - seawater backs up through storm drains before surface flooding is even visible.[6] The Southeast Florida Regional Climate Compact tracks increasing hours above mean high tide across Broward, Miami-Dade, Palm Beach, and Monroe counties, and King Tide events (fall perigean spring tides) now routinely flood roads and properties along the Intracoastal Waterway.[7]

Norfolk / Hampton Roads, VA

Norfolk combines sea level rise with significant land subsidence, making it one of the fastest-sinking populated areas on the East Coast. Sewells Point (home to Naval Station Norfolk, the world’s largest naval base) now regularly records 20+ high-tide flood days per year. The Mid-Atlantic region overall has seen a more than 200% increase in flood days vs. 2000, with an observed median of 17 days in the 2023–24 meteorological year - the highest of any region.[3]

New York & Atlantic City

Atlantic City, NJ and the New York metropolitan area have seen sharp increases in high-tide flood frequency over the past decade. The Battery (Manhattan), Atlantic City, and Kings Point (Long Island Sound) all regularly exceed 20 flood days per year in the mid-2020s - levels that would have been exceptional a decade earlier.[3]

Galveston & the Western Gulf

The Western Gulf coast regularly records 20+ high-tide flood days per year at stations including Galveston and Eagle Point, TX. The region’s ~300% increase vs. 2000 is driven by the combination of sea level rise and land subsidence, which is particularly acute along the western reaches of the Gulf Coast.[3]

Lake Mead: Water Supply Under Pressure (2000–2026)

Figure 3. Lake Mead elevation at Hoover Dam, 2000–2026 (December year-end, annual low, and 2026 monthly). The reservoir declined from ~92% of capacity in 2000 to a record low of 1,040.92 feet (~27% of capacity) in July 2022 - its lowest level since initial filling in 1937. Conservation agreements and a wet 2023 winter produced a brief recovery, but a poor 2026 snowpack erased it: by late July 2026 the reservoir stood at 1,041.2 feet (~27% full), within a third of a foot of the all-time record. Note that storage does not scale linearly with elevation - percentages shown are Reclamation-reported contents. The orange line marks the 1,075-foot Tier 1 Shortage trigger, below which mandatory delivery cuts apply to Arizona and Nevada. Source: U.S. Bureau of Reclamation (elevations verified 8/1/2026).[8]

Key Observations

Context & Discussion (continued)

The Colorado River Basin & Dependent Populations

The Colorado River system supplies water to approximately 40 million people across seven states and Mexico, irrigates roughly 5.5 million acres of farmland, and generates hydroelectric power at multiple dams. Lake Mead and Lake Powell are the system’s two largest reservoirs, with a combined capacity of approximately 50 million acre-feet. The system went from 95% full in 2000 to near-record lows by 2022; in July 2026, combined Mead–Powell storage set a new record low. The 25-year period from 2000 to 2024 was the driest in over 1,200 years of record-keeping, based on paleoclimate reconstructions.[9] Western snowpack - a critical source of reservoir inflows - has grown increasingly volatile. Sierra Nevada snowpack, which supplies roughly 30% of California’s water, reached its lowest level in 500 years in April 2015 (0.5% of average statewide; no snow at the Phillips Station survey site), then swung to 237% of average in 2023, held near average in 2024–25 (110% and 96%) - and collapsed again in 2026 to 18%, the second-lowest April 1 reading on record, with Phillips again snowless after record March heat melted the pack a month early.[11]

Figure 4. California April 1 statewide snowpack, percent of average (selected years). The swing from 0.5% (2015) to 237% (2023) to 18% (2026) illustrates why “average” is becoming a poor planning assumption for Western water supply - and why reservoir storage and groundwater rules, not annual precipitation, are the binding constraints for development. Sources: California DWR April snow surveys; DWR data via CalMatters.[11]

Southern Nevada (Las Vegas) has adapted more aggressively than most Colorado River users. The Southern Nevada Water Authority implemented tiered water pricing, removed over 200 million square feet of ornamental grass, and recycled nearly all indoor water back to Lake Mead. Per-capita water consumption in Las Vegas declined roughly 47% from 2002 to 2022 even as the metro population grew significantly. Despite these efforts, Nevada’s Colorado River allocation (300,000 acre-feet per year) is the smallest of the three Lower Basin states and is subject to shortage-tier cuts.[9]

Arizona faces the most direct impact from Colorado River reductions. The Central Arizona Project (CAP) aqueduct delivers approximately 1.5 million acre-feet per year from Lake Mead to Phoenix, Tucson, and agricultural users in Central Arizona. Under shortage conditions, Arizona absorbs the largest mandatory delivery reductions among Lower Basin states. In parallel, the Arizona Department of Water Resources determined in June 2023 that all physically available groundwater in the Phoenix Active Management Area is fully allocated, meaning new suburban subdivisions outside of designated municipal service areas can no longer rely on local groundwater to meet the state’s 100-year Assured Water Supply requirement.[10]

Next: Phoenix - Water, Growth & Industrial Demand

The Phoenix metropolitan area sits at the intersection of multiple water supply constraints: declining Colorado River allocations, fully allocated groundwater, and a 100-year assured water supply framework that is actively being renegotiated. At the same time, Phoenix is attracting significant water-intensive industrial investment - semiconductor fabrication facilities (TSMC, Intel), hyperscale data centers, and advanced manufacturing - all of which require reliable water and electricity in a region where both are under increasing pressure. The next page in this section examines Phoenix as a case study in the tension between Sun Belt growth and long-term resource sustainability.

What to Watch in 2026

Sources to Track Climate Risk at the MSA Level: