By State › National Patterns

National Patterns

Every state page on this site was built independently, one at a time, each claim sourced on its own terms. This page is different: it's what shows up when you step back and cross-reference them all at once. None of it is new information, it's all already sitting on the individual pages, but a few real patterns only become visible at that scale.

Washington, D.C. and Puerto Rico aren't fully folded into the counts below yet

The breakdowns on this page (water-law doctrine counts, carry-law age groups) were built from the 50 states before D.C. and Puerto Rico had their own pages. Both are shall-issue for carry and don't fit the riparian/prior-appropriation frame for water law, similar to Hawaii's exception below, but re-running the actual counts and category groupings below to include them properly is still a separate pass, not yet done.

Water law splits almost exactly on geography

Forty-eight of the 49 states in this collection name a specific water-rights doctrine (Hawaii is the exception, discussed below). Grouping those 48 by doctrine produces a near-perfect geographic divide.

Doctrine	Count	Pattern
Riparian (reasonable-use)	30 states	Nearly every state east of the Mississippi/100th-meridian line
Prior appropriation	11 states + Utah's flagship	Nearly every state west of it
Explicit hybrid of both	7 states	Oklahoma, Nebraska, South Dakota, Texas, and Iowa, plus California and Alaska
No general doctrine named	1 state (Hawaii)	Rainwater catchment is common enough locally that the page centers on catchment rules directly

The hybrid cluster is mostly the Great Plains

Five of the seven hybrid states, Oklahoma, Nebraska, South Dakota, Texas, and Iowa, sit in or on the edge of the Great Plains, the historical transition zone between the humid East and the arid West. That's not a coincidence this site introduced; it matches real legal-geography scholarship about the 100th meridian as the rough line where riparian assumptions about ample rainfall stop holding and appropriation-style scarcity management takes over. California and Alaska are the two hybrids that don't fit the Plains pattern, each for its own local reason (California's mixed climate and settlement history; Alaska's 1966 Water Use Act deliberately folding both doctrines into one statute).

Why Hawaii doesn't fit the same frame

Hawaii's page doesn't skip a water-rights doctrine by oversight. Rainwater catchment there is a mainstream primary water source for tens of thousands of residents, not a supplemental practice layered on top of a river-and-aquifer allocation system the way it is almost everywhere else on the mainland, so the practically relevant law is catchment-specific rather than a general doctrine.

Carry law spans the entire national spectrum, and one Supreme Court decision is a hinge point

Twenty-seven of the 49 states in this collection are permitless-carry states, and Utah's own flagship coverage makes that 28 of all 50. Splitting those 27 by minimum age turns up a three-way pattern, not a simple trend line.

Minimum age	Count	States
18	12 states	Alabama, Arkansas, Idaho, Indiana, Louisiana, Mississippi, Montana, New Hampshire, North Dakota, South Carolina, South Dakota, West Virginia (2026)
21	13 states	Alaska, Arizona, Florida, Georgia, Iowa, Kansas, Maine, Nebraska, Ohio, Oklahoma, Tennessee, Texas, Wyoming
19	1 state (Missouri)	Doesn't match either cluster
No distinct age set	1 state (Vermont)	Never had a permit system to attach an age requirement to in the first place

The 22 states that still require a license or permit range from routine shall-issue systems to some genuinely distinctive structures: Rhode Island splits carry-permit authority between local police (shall-issue) and the Attorney General (may-issue) for the identical permit, so an applicant's odds depend on which office they use. Hawaii's system changed more abruptly than any other state covered here, from decades of effectively no-issue to genuinely shall-issue almost overnight after the Supreme Court's 2022 Bruen decision, a turning point that also shows up explicitly on California's, New York's, and Connecticut's pages.

Vermont and New Jersey bookend the whole spectrum

Vermont has never required a carry permit at any point in its history, permitless since Article 16 of its 1777 constitution. New Jersey, at the opposite end, recognizes zero other states' carry permits and layers on some of the most restrictive purchase and magazine rules covered on this site. Both are real, current state law, on the same country's map.

A meaningful share of disasters trace to institutional failure, not weather

At least nine states' flagship or co-flagship risks have an identifiable human or institutional point of failure behind them, not just severe weather:

State	What failed
Ohio	East Palestine train derailment
New Mexico	Hermits Peak/Calf Canyon fire, ignited by an escaped U.S. Forest Service controlled burn
West Virginia	Elk River chemical spill
Michigan	Edenville and Sanford dam failures
Maryland	Francis Scott Key Bridge collapse, a vessel strike
South Dakota	Canyon Lake Dam failure, compounding the 1972 Black Hills flood
Idaho	Teton Dam failure, on its first reservoir filling
Nebraska	Spencer Dam failure during the March 2019 bomb cyclone
Arkansas	Guy-Greenbrier earthquake swarm, triggered by wastewater injection wells

That's not a small footnote category. Nearly one in five states covered on this site has a flagship risk that traces back to a specific piece of infrastructure or a specific decision, not to weather alone.

Some hazards only make sense as multi-state systems

Several risks on this site were deliberately not re-explained on every state that shares them; each state's page covers its own angle and points to the others rather than repeating the same regional data five times.

Shared hazard	States	How it was split
New Madrid Seismic Zone	Arkansas, Illinois, Missouri, Tennessee	Missouri as literal epicenter; the others cover their own exposure and population stakes without restating the zone's probability figures each time
Yellowstone region	Idaho, Montana, Wyoming	Each state drew a different hazard from the same geology: Idaho's Teton Dam, Montana's Hebgen Lake earthquake, Wyoming's caldera itself
Cascadia subduction zone	Oregon, Washington	Oregon covers the shared fault system in depth; Washington points back to it rather than duplicating the numbers
Gulf Coast hurricane corridor	Alabama, Florida, Louisiana, Mississippi, Texas	Same coastline, same storm family, five structurally different stories (levee failure, direct surge, land loss, grid isolation, and more)
Atlantic sea-level-rise cluster	Delaware, Florida, Maryland, Virginia	A standing, ongoing condition rather than a single event, with Delaware's rate, roughly twice the global average, the most severe documented on the site

"Record" flood and storm levels have a shrinking half-life

Several pages independently landed on the same observation: a flood record isn't the stable ceiling it sounds like.

Maine's January 2024 coastal flood broke a Portland tide-gauge record that had stood for 46 years.
Vermont's July 2023 flood broke its own predecessor's Winooski River crest record from Tropical Storm Irene in under 12 years.
Indiana's August 2026 floods broke a White River crest record at Anderson that had stood since 1913, 113 years.
New York's 2021 Hurricane Ida flooding killed people in basement apartments sitting entirely outside the officially mapped 100-year floodplain, a related but distinct problem: the historical map itself, not just the historical record, understated the real risk.

Two different failure modes, worth telling apart

A record broken sooner than the last one suggests conditions are actively changing. A record that was never exceeded but still failed to capture real risk, New York's case, suggests the historical baseline itself was incomplete from the start. Both point toward the same practical conclusion for a household: don't treat a "record" or a "mapped floodplain" as a hard boundary on what's possible where you live.

A real "zero direct deaths" success cluster

Not every pattern here is a warning. Several catastrophic-scale floods produced no direct deaths, a genuine credit to warning and evacuation systems rather than an absence of severity:

Minnesota's 1997 Red River flood ($3.5 billion in damage, zero deaths)
Iowa's 2008 Cedar Rapids flood (an 11-foot record-breaking crest, zero deaths)
Rhode Island's March 2010 floods (the worst in over 200 years, zero direct deaths)
North Dakota's Grand Forks, the epicenter of that same 1997 Red River flood Minnesota's page covers, though a downtown fire that broke out during the evacuation did claim structures the flood alone hadn't reached

About these numbers

Every figure on this page was computed directly from the 49 individual state pages in this collection (Utah lives in the main manual as this site's flagship edition and isn't part of the count) by searching the actual published content, not recalled from memory. That also means this page is a snapshot, not a permanent tally: if an existing state page is revised, a law changes, or new states are added to a future edition, the counts here should be recomputed against the current pages rather than assumed to still hold. Treat this page as a guide to where to look, not a substitute for reading the specific state's own laws or risks page for anything that matters to a real decision.

Sources

Every claim above traces to a specific state's By State page; follow the state name in the tables to its own laws or risks page for full sourcing.