Hurricane Sandy's destructive rampage across the Northeast inflicted at least $50 billion to $60 billion in damage, according to early estimates. That's not counting the death toll from the storm—110 dead and rising. It's also not counting all the hardship that can't easily be quantified. (It's miserable to sit at home without power for days in winter weather, even if that barely registers in the GDP numbers.)
Still, that $50 billion to $60 billion is clearly a massive number by any yardstick. So how does Hurricane Sandy compare alongside past U.S. hurricanes? Well, it's either the second most destructive storm ever — or much further down the list. It all depends on how you count.
Last year, the National Hurricane Center tried to rank (pdf) the deadliest and most expensive storms in U.S. history. If we only look at pure economic damage adjusted for inflation, then Sandy is on pace to be the second or third costliest hurricane since 1900, topped only by Hurricane Katrina in 2005 and on par with 1992's Hurricane Andrew
Costliest hurricanes, in constant 2010 dollars
1. Katrina, 2005, $105.8 billion
2. Sandy, 2012 $50 billion (est.)
3. Andrew, 1992, $45.6 billion
4. Ike, 2008, $27.8 billion
5. Wilma, 2005, $20.6 billion
6. Ivan, 2004, $19.8 billion
7. Charley, 2004, $15.8 billion
8. Irene, 2011, $15.8 billion
9. Hugo, 1989, $9.7 billion
10. Rita, 2005, $11.8 billion
Notice something striking about this list. Even after adjusting for inflation, the costliest storms have all occurred in the past decade. So does that means the hurricanes themselves have been getting more powerful and destructive of late?
Not necessarily. After all, the U.S. population has also been growing, our cities have been swelling, and our living standards are rising. That means a similar-sized hurricane will do more economic damage in a given area today than it did back in 1917. That's why the National Hurricane Center also offers a second ranking. Here are the costliest storms since 1900 if you adjust for inflation, population, and property values. This, in other words, is what those storms likely would have cost if they hit today:
Costliest hurricanes, adjusted for inflation, population, and housing
1. Southeast Florida, 1926, $164.8 billion
2. Katrina, 2005, $113.4 billion
3. Galveston, 1900, $104 billion
4. Galveston, 1915, $71.4 billion*
5. Andrew, 1992, $58.6 billion
6. Sandy, 2012, $50 billion (est.)
7. New England, 1938, $41.1 billion
8. Southwest Florida, 1944, $40.6 billion
9. Southeast Florida/Lake Okeechobee, 1928, $35.3 billion
10. Ike, 2008, $29.5 billion
Notice that Sandy ranks a bit lower on this list. What's more, many of the 10 most destructive hurricanes came in the early part of the century. Still, even when we adjust for all of these different variables, eight of the 30 most destructive storms have occurred after the year 2000.
There seems to be a pattern here. The National Hurricane Center report notes that between 1961 and 2000, there was actually a relative lull in the frequency of hurricanes hitting the United States. But storm activity then went up again after 2000. "[L]andfall activity during the 2000’s has picked up significantly," the report notes, "and is now near the frequency seen in the very active 1950's."
And what about the future? As humans keep warming the planet, climate scientists predict that the frequency of hurricanes will likely "either decrease or remain essentially unchanged” overall. The bad news is that what hurricanes do form will likely be stronger, with fiercer winds and heavier rains. That's because the oceans are warming, and the air is becoming more saturated with moisture, both of which can make hurricanes more powerful. What's more, as global sea-levels keep rising, that will worsen flooding and storms surges from both big hurricanes and smaller storms.
That said, as our first list shows, hurricane damage will likely increase regardless of how global warming affects storms. Americans keep getting richer and keep building on coastal areas that are prone to storms. (Note that in some cases, as Steve Nash has argued here, government agencies such as FEMA and the Army Corps of Engineers have been promoting coastal development by either subsidizing flood insurance or approving shoreline hardening projects.) Those factors alone suggest that we'll keep seeing bigger and bigger dollar figures in the disaster headlines.
--Here's the 2008 paper by Roger Pielke Jr., Christopher Landsea, and others explaining how to compare hurricane damage over time.
--The above figures look at economic damages, but hurricanes can also kill people. According to the National Hurricane Center, the Galveston hurricane of 1900 killed 8,000 people and remains the deadliest U.S. hurricane on record. Katrina is third at 1,200 deaths caused by the storm. Note that the improvement in hurricane forecasting over the years has likely helped here.