Hurricane Isabel, September 2003

Astronaut Ed Lu snapped this photo of the eye of Hurricane Isabel from the International Space Station on September 13, 2003 at 11:18 UTC. At the time, Isabel was located about 450 miles northeast of Puerto Rico. It had dropped to a Category 4 hurricane on the Saffir-Simpson Hurricane Scale, packing winds of 150 miles per hour with gusts up to 184 miles per hour.

After originating in the eastern Atlantic west of the Cape Verde Islands, Isabel became the second major hurricane of the 2003 Atlantic season when it was declared a Category 3 storm by the National Hurricane Center on September 8. Over the next four days, Isabel strengthened into an extremely powerful Category 5 hurricane with winds estimated at 160 mph before dropping to a Category 4 hurricane on September 13.

This photo shows the structure of Isabel's eyewall. The image, ISS007-E-14745, was taken with a 180mm lens on a digital camera. Image courtesy of Mike Trenchard, Earth Sciences & Image Analysis Laboratory , Johnson Space Center. 

Although she had subsided from a Category 5 to a Category 2 storm, Hurricane Isabel still packed considerable punch as she came ashore between Cape Lookout and Cape Hatteras on North Carolina’s Outer Banks on September 18, 2003. Isabel grew to a massive size just before she hit land, with hurricane-force winds radiating as far as 185 km (115 miles) from the eye, and tropical storm-force winds extending roughly 555 km (345 miles) outward from the eye.

The still image above, and the accompanying time series, was acquired by the GOES satellite at 2:02 PM EDT, September 18, 2003. The movie begins as Hurricane Isabel was approaching Cape Lookout on the morning of September 18. As the eye of the storm moved inland, Isabel veered to the north and weakened into a tropical storm, losing much of its structure. The storm charged up the western side of the Chesapeake Bay and continued on its northward surge until it eventually fell apart over Ohio.

With its relatively high winds and heavy rains, Isabel pounded heavily populated areas in North Carolina, Virginia, Washington, D.C., Maryland, and Delaware, claiming at least 35 lives and leaving millions without power. Due to the widespread damage caused by the storm, President Bush declared major disaster areas in each of those states.

Hurricane Isabel   Robert Leverett
  Sep 15, 2003 10:01 PDT 


A big hurricane hitting the Northeast will most likely change some
Rucker indexes. Perish the thought, but it could happen. We all live
with that threat. Small places are exceptionally vulnerable. As much as
I worry, I am also somewhat excited about the test of survivability of
different kinds of forests and forest structures.

In a way, all this is old hat to Lee on Minnesota. He lives with the
threat of big weather events that go almost unnoticed and unreported by
the self-important eastern seaboard.


RE: Isabel   NR, Cook Forest Env. Ed.
  Sep 19, 2003 12:48 PDT 


'Tropical Storm' Isabel caused no major problems at Cook Forest (power outages, phone lines down, roads closed, etc.). I'm not sure of the current Rucker status, but all we really got here was some heavy drizzle and an occasional gust to maybe 30mph... nothing more than a regular blustery day.

Re: Hurricane Isabel    Colby Rucker
   Sep 24, 2003 12:54 PDT 


After six days without power, I'll rejoin the civilized world, on a rather
selective basis, as before. I'm glad to hear that Isabel treated CFSP
rather gently. Locally, the high tides in Annapolis were the national news,
and the highest I've seen. We were fortunate to escape torrential rains,
but the winds were strong, from the northeast, and leveled trees all over.

I've seen at least 25 fair-sized trees down in my woods, damaging numerous
smaller trees. In addition, half a dozen black cherries went down closer to
the house, providing some welcome firewood from an otherwise nuisance
species ranked # 59 out of 65 on my list.

The rather uniform intensity of the winds was in contrast to the violent
gusts of Hurricane Floyd several years ago, which took down a swath of white
oaks and other sturdier trees. I found the results from Isabel quite
interesting, suggesting several factors which seem to support my contention
that the original forest was lower, competing more by spread than by height.

Trees uprooted were primarily tuliptree, chestnut oak, and red maple.
Diameters were mostly 16"-32". It appeared that more slender specimens
survived by having low sail area, and less trunk weight to contribute to
momentum.   Larger trees with a well-developed crown survived, although
having a greater sail area. Although heights ranged up to 140', it appeared
that a big crown is essential to provide sufficient nutrients for a
well-developed root system.

Most woodlands are logged long before this transitional stage is reached.
In one instance, tall chestnut oaks apparently "sheltered" by a large
tuliptree were blown down, while those to either side escaped. The
tuliptree had forced the oaks into a race for height which they could not
win. Their resources went into height development, which resulted in tall
handsome stems. Once the stems were heavy enough, there was sufficient mass
for windthrow. A small crown and being on the lee side of the poplar gave
little protection once the limited root system was overwhelmed by sufficient
trunk mass.

Chestnut oaks to either side had less tuliptree competition, and were
shorter, with more divergent crowns producing more nutrients, with enough
excess to stimulate greater root development. Another large tuliptree did
essentially the same thing. Some weeks ago I thought the more slender
competitors would progressively shade, and therefore reduce, the lower
portions of the tuliptree's crown, but there is danger to the more slender
competitor, and the big tuliptree now stands alone.

Of course, the chestnut oaks made a second mistake by venturing into areas
characterized by tuliptree, pawpaw, red maple, northern red oak, etc.
Although the form and height of such specimens is noteworthy, they cannot be
windfirm in such habitat. The same can be said of scarlet oaks, with the
tallest specimens being found at the more fertile fringes of their typical
habitat. Most of the chestnut oaks blown down were in low-slope positions,
where they grew quite happily for a hundred years, but had, we see, ventured
beyond their more permanent habitat.

The red maples uprooted were part of a continuing trend which suggests that
they, despite their shade tolerance, are of earlier succession than most
mature woodlands would suggest. Although losses of various species opened
up the canopy, the canopy is more likely to be filled by nearby trees
increasing their spread, rather than vertical growth by new or small
specimens. This process is different, and more interesting, than that
following Hurricane Floyd.


Re: Hurricane Isabel
  Sep 25, 2003 16:08 PDT 

What you described as an impact of Hurricane Isabel sounds very similar to
the damage we experienced during an ice storm on our steeply sloping land in WV.

The tree species we lost the most of shared the physical properties that you
mentioned. Many of the largest and most vigorous trees saw their tops
partially broken or shredded but the surrounding skinny interlopers were often nuked,
flat or shattered.

Excellent observations.

Russ Richardson
RE: Hurricane Isabel   Dale J. Luthringer
  Sep 26, 2003 20:40 PDT 


Glad to hear you're back in civilization, although you may not welcome
the plague of multiple e-mails in your box. 6-days?! That would give
me a good excuse to finish up last year's venison before it went bad!
Hope your house didn't suffer any damage.

I know some would consider this next question a rub on your age, but who
else can we go to for such sage advice? How did Hurricane Floyd compare
to Hurricane Agnes in your area in 1972? Our retired park manager
remembers Agnes well. I'm not sure about the extent of downed trees
back then, but the Clarion River made the Park Office into an island and
put about 8ft of water in its basement.

Those "nuisance" black cherries sure do burn pretty though, along with
that nice 'snap, crackle, and pop' sound.

Re: Hurricane Isabel   Colby Rucker
  Sep 26, 2003 23:39 PDT 


As we get older, our experience is punctuated by various events, and
hurricanes seem to top the list, being a convenient source of conversation
in a given area. Locally, storms in 1933, 1954, 1955, 1972, 1979, 1999,
and 2003 affected Anne Arundel County.

The 1933 storm was before my time, but it came right up the Chesapeake Bay,
and caused severe wind damage, beach erosion and coastal flooding. Hazel,
in 1954, was a massive storm that passed over this area, causing widespread
wind damage, including breakage to the Liberty Tree and other big trees.
Chainsaws were almost non-existent, but no one was in much of a hurry, and
cleanup was done as convenient, sometimes months later. Rainfall was
considerable, but coastal flooding was modest. Connie, in 1955, was less
damaging, but caused higher levels at tidewater.

Agnes, in 1972, caused little if any wind damage, but brought rains of ten
inches or more. The most severe flooding was in Pennsylvania, but local
streams of even modest size became torrents, eroding their banks, and
causing dramatic blockages of uprooted trees and all sorts of debris. The
county boundaries along the Patuxent River, Deep Run, and the Patapsco River
were the scene of much destruction, with many homes and businesses
destroyed, and the bay was covered with all sorts of logs and debris swept
down the Susquehanna. I had several stream-clearance contracts with the
Corps of Engineers, but trees on most private properties were unscathed.

David, in 1979, caused considerable wind damage to trees at estates along
the western shore of the bay, but little inland. Floyd, in 1999, was a big
storm, with strong winds, but most damage came from sudden gusts of
scattered occurrence. The Liberty Tree evidenced a split near the 1954
injury, but 45 years had changed our society to one menaced by lawsuits and
lawyers, and the tree, still vigorous, was removed after being deemed unsafe
by five tree experts and the college, all eager to avoid any legal

Isabel was a strong storm, but the winds were of rather uniform intensity.
Its path pushed water up the bay and to the western shore, causing coastal
flooding not equalled since 1933. Tree breakage was rare, but a wet season
induced much windthrow, which caused problems in a landscape much more
intensely developed than before.

About 95% of the county lost power. Outages (six days here) were more
prolonged than even Hurricane Hazel. Baltimore Gas and Electric had lost
hundreds of millions in an ill-fated bid to wheel and deal energy on a
national basis, and had cut customer service to make up for it. They had
consolidated their crew locations, and closed local yards. They had been
telling callers they didn't remove hazardous trees over wires or
transformers, or even remove trees that had fallen on their wires. They'd
ask if the wires were sparking, and tell the caller to contact someone else,
perhaps the county, to no avail. They actually were still contracting tree
work, but had cancelled their contract with Asplundh, and used tree trimmers
from Pennsylvania, who worked four days a week.

Without Asplundh, there were no local crews, and it took days to get help in
from Ohio and other areas. Without a large resident workforce of Asplundh
workers (who did private work quite reasonably on weekends) private tree
outfits have a near monopoly, and their prices are predatory. Such is the
case in a more anonymous society, with little interest in one's reputation.
Everyone seems in a hurry, and county crews, replete with lots of heavy
equipment, are busy everywhere cleaning up in the land of tax hell.

So, each hurricane was different, not only the storm itself, but also in its
effect, due to continuing changes in our society.

RE: Hurricane Isabel   NR, Cook Forest Env. Ed.
  Sep 27, 2003 11:43 PDT 


Thanks for the account of these past hurricanes. Let's see, that's almost 50's years of a living history lesson!

PA received close to 10" of rain from Agnes. We have not observed flooding on the Clarion to those flow levels since then. Our worst flood event was during the same storm that created the "Johnstown Flood" on 3/17/36. Flood stage at the Park Office is at 13ft. The Johnstown Flood storm resulted in a river depth of 19ft at the Cooksburg Bridge with a flow of 56,000ft^3/sec. A normal summer depth at this gauge would be from 2-3ft and flow of 600-800ft^3/sec.

We received some rain from Floyd in 1999, but nothing compared to Philly who got 6.63". Cook Forest did experience a heavy rain event 7/18/98 with close to 6" of rain in a 24hr period. Flash flooding stripped away bridges, vehicles, roads, and houses. It took them about 3 years to replace all the bridges that were washed away on the side roads.

2003 has been one of the wettest years on record since my tenure at Cook Forest. The saturated soils and recent microbursts have opened up many areas of the canopy in our old growth sites. The Forest Cathedral area is much more opened up now than it was 7 years ago. This would be a great opportunity for quicker regeneration if we could get a handle on the high deer density.