While I certainly welcome this debate and encourage the discussion, I did want to provide my perpective on the topic... since I was actually there.
First, I want to thank everyone for the great comments on the video, in my 25 years of chasing it still remains the most amazing footage I've been fortunate enough to capture, and it's great that people find it so fascinating and that it can be used to convey how powerful and dangerous tropical cyclones are.
For the specifics on Hugo's intensity at the time of landfall in Puerto Rico, Derek is absolutely correct, from a conventional perspective. The official NHC Preliminary Report and Best Track data have the storm's maximum sustained winds at 110kts (operationally this is rounded up to 130mph), which means "officially" Hugo was right at the cutoff between Category Three and Four at the time it passed over the island of Vieques and subsequently over extreme NE Puerto Rico.
That said, the winds that impacted Vieques, Culebra and NE Puerto Rico from just north of Ceiba/Roosevelt Roads to the Rio Grande area, especially in the areas of Fajardo and (where I was) in Luquillo, were easily of Category Four strength. After reviewing my own footage, as well as many others, over the past 18 years, as well as personally intercepting numerous tropical cyclones (over 40), of varying intensities...I am confident that the highest surface winds on my video are sustained near 115kts (135mph) with gusts between 130-140kts (150-160mph) and it is entirely plausible, especially given the damage that we observed, that an instantaneous peak gust may have reached 150kts (170mph). Note that my estimates are intended to convey 'normalized' values for a standard elevation of 10m (33ft) at an exposed coastal location...they are not taking into account localized acceleration of wind speeds around structures or winds at higher elevations, which were likely greater than even my estimate above. I want to stress that these estimates were not made lightly and are the product of years of stringent analytic review and debate...they are not intended to inflate the appeal of the video or make people think that what my chase team experienced was stronger than what it was.
So how is there such disparity between the "officially" documented data and the experiential observations? This very question has fueled years of debate, and I will touch on a couple of the more obvious items below. Ultimately my hope is that the HRD Re-analysis effort, that has been underway for a few years, will revise Hugo's best-track intensity (up to 115kts) for both the positions over Vieques and landfall at Fajardo. I certainly plan to lobby hard for this...haha.
Ok...so here are my perspectives on some of the more common points of debate regarding Hugo's Puerto Rican landfall:
Location of Hugo's wind maxima:
A tropical cyclone's surface windfield distribution can be highly variant to the "typical" right-front quadrant conventionality, as observed in numerous instances. At any given time, the wind maximum can even be transient, with the development of intense convection in any quadrant. Detailed radar analysis of Hugo crossing Puerto Rico has been elusive, but some satellite imagery (like on the cover of the US. Dept. of Commerce's Natural Disaster Survey -- http://www.nws.noaa.gov/om/assessments/pdfs/hugo1.pdf) near the time the storm moved over Luquillo showed the most intense convection from the northern through southwestern eyewall, as evidenced by the brighter, more bulbous, convective tops. The north and northeastern extremity of this "hot spot" in the eyewall is what would have passed over Culebra, with the northwestern portion passing over Vieques and later over my location. This area is likely where the strongest surface winds would have been located, since the intense convection would have been translating the higher winds aloft, down to the surface. Indeed a 700mb wind-field analysis from 17/20Z through 18/06Z indicated that the peak winds were distributed from the eastern through northern eyewall, coinciding with the location of the most intense eyewall convection at that time. Subsequent to that, the most intense convection apparently migrated to the northern through western eyewall and this supports the premise that the surface wind maxima likely followed and rotated from the eastern through northern portions of eyewall to the northern through western portions of the eyewall, impacting both Culebra and Northeastern Puerto Rico, in turn.
Unofficial Observations:
The most dramatic observation, which speaks directly to Hugo's overall intensity, was a 148kt (170mph) gust from the yacht "Night Cap", in harbor on the island of Culebra (25 miles east of Luquillo). This gust is considered credible and is officially noted in the NHC Preliminary Report. Assuming a standard gust ratio of 20-25%, yields a potential 1-min sustained surface wind of 116-122kts (133-140mph). Additionally, the 148kt observation was reported just prior to the anemometer failing, so it is plausible that even higher winds occurred at that location and were not recorded. Miles Lawrence inexplicably left this detail out of the report. Also unavailable is the exact time of that observation, however, it seems likely that this would have occurred while Hugo was very near, or centered over, Vieques...at the time the "best track" indicates that maximum sustained winds are 110kts...so, in my estimation, there is some significant discrepancy here.
Roosevelt Roads NAS and other surface observations:
While the Roosevelt Roads NAS observation of 90kts (98mph) gusting to 104kts (120mph) was the highest official recorded wind from a land-station in Puert Rico, and is often used to 'represent' the intensity of Hugo in Puerto Rico as a whole, this observation was made in the western eyewall where the direction of the strongest winds was from the north-northwest or northwest, meaning that: 1. these winds were from an over-land direction, as opposed to onshore... and 2. they would have been partially blocked by the moutainous terrain of the El Yunque peak. Both of these factors likely contributed to a significant reduction in the observed windspeeds in the area of Ceiba and Roosevelt Roads. As with most tropical cyclones, there is a lack of reliable/available surface wind observations during Hugo's passage through the Caribbean. As such, we are left to estimation from other sources...recon obs, post-storm damage analysis and direct visual observation...my personal opinion being that the latter two are the most truely evaluative methods, when conducted by qualified individuals.
Nuances to "officially" documented observatios/data:
It becomes very easy to take officially documented data directly at face value and to make inferences from those that might lead to one conclusion. However, without knowing the nuances to the specific observation, it is very easy to take things out of context...as an example... In the official NHC Preliminary Report on Hugo, Miles Lawrence indicates that the lowest pressure in Luquillo, Puerto Rico is 956mb (28.23in) at 1300UTC...additionally, the report shows the minimum pressure at Roosevelt Roads NAS as 946.1mb (27.94in) at 1250UTC. Analyzing these two values, I would normally conclude that either Hugo weakend by 10mb between the time of landfall and when the center passed over Luquillo...or, that Luquillo didn't intersect the pressure minimum in the storm. Neither of these are true... the 956mb observation in Luquillo was actually made by our chase team...the reading coming directly from Jim Leonard's barometer (which can be seen in my video). This particular reading was actually made right at the end of the lull associated with the eye passage. We had been walking around Luquillo, during the eye, filming damage for over 30 minutes before returning to the garage where our car was, just before the 2nd half started. This is when the observation was made. At that time, the pressure was already rising rapidly, and it is quite likely that the minimum pressure in Luquillo, 15-20 minutes prior, was probably right around 946mb. These type of nuances are pervasive throughout many documented observations (both official and unofficial) for virtually all types of meteorological events, so it really does become very hard to evaluate everything correctly...in the case of Hugo, I've spent the last 18 years refining this evaluation.
Post-storm surveys and analysis:
There have been numerous post-storm surveys of Hugo's damage throught all of the areas the hurricane affected, both in the Caribbean and the U.S. The most exhaustive of these was the Natural Disaster Survey Report (previously linked) conducted by U.S. Dept. of Commercer/NOAA. The 13-person team was comprised of representation from NOAA, NWS, NOAA-ERL, and NESDIS covering diverse fields, with the goal of documenting an objective appraisal of Hugo's impacts and presenting findings and recommendations. This report was published in May, 1990 (note that this is fully six months after the NHC published their preliminary report and best-track observations for Hugo on November 15, 1989) and the findings are of significant interest, since this team did take an "evaluative" approach to understanding all the pieces to the puzzle, rather than just analyzing the available empirical data. In some cases the findings from this report stand in stark contrast to other "official' documents on Hugo. Here are some exceprts:
Pg xi - Executive Summary - "During the hurricane's approach to the Leeward Islands, a NOAA research aircraft east of Guadeloupe measured winds of 160 MPH and a central pressure of 27.1 inches or 918 millibars (mb,=). This qualified Hugo as a Category 5 storm -- the highest -- on the Saffir-Simpson Scale (see Appendix B). The storm was rated as Category 4 when it pounded the Virgin Islands, Puerto Rico and South Carolina."
Pg 1 - Chapter I - Hurricane Hugo: The Event and its Impact - "Hurricane Hugo was the strongest storm to strike the United States since Camille pounded the Louisiana and Mississippi coasts in 1969. At one point east of Guadeloupe, a NOAA research aircraft measured winds of 160 MPH and a central pressure of 27.1 inches (918mb) which rated Hugo as a Category 5 -- the highest -- storm on the Saffir-Simpson Scale. When Hugo struck the Virgin Islands, Puerto Rico and the Carolinas, it was classified as a Category 4."
"...A couple hours after midnight Monday, September 18, the hurricane's eye crossed the southwestern coastline of St. Croix near Frederiksted severely damaging this Dutch-style town. Maintaining 140 MPH maximum winds, the hurricane destroyed or damaged more than 90 percent of the buildings on St. Croix...No official wind velocities were recorded on the island. Weather observers had abandoned the exposed airport site. Based on the Fujita Tornado Intensity Scale (see Appendix C), damage surveys indicated that there was widespread upper (F1) and (F2) straightline wind damage. Thus, wind speeds as high as 161 MPH were estimated. Some localized damage appeared to be (F3) but might have been caused by topographic channel effects or microbursts."
"With Hugo's foward speed slowing to 9 MPH over the 12-hour period, St. Croix experienced strong winds both before and after the passage of the eye. From the lie of downed power poles and from the entire island's vegetation, which was literally stripped bare, it was deduced that all of St. Croix experienced the storm's maximum winds."
"Subsequent to its Virgin Island course, Hugo shifted slightly northward. After sunrise Monday, September 18, the hurricane increased its forward speed as it crossed over the Puerto Rican islands of Vieques and Culebra and skirted the northeast tip of Puerto Rico near Fajardo. As the eye passed over Vieques, maximum winds were estimated at 132 MPH. At Culebra just north of Vieques, an unofficial gust of 170 MPH was reported by the yacht, Night Cap."
Pg 4 - Chapter I - Hurricane Hugo: The Event and its Impact -"On Puerto Rico proper, peak gusts at Roosevelt Roads Naval Air Station, 10 miles south of Fajardo, were recorded at 120 MPH. Sustained winds hit 98 MPH. The hardest hit areas were Fajardo and Luquillo Beach on the northeast coast where damage paralleled that of St. Croix."
Pg 30 - Chapter IV - An Evaluation of the Processing, Interpretation and Dissemination of NWS Information - "During Hugo, storm surges of up to 8 feet were predicted for exposed coastal areas in the Virgin Islands and Eastern Puerto Rico. Storm surges of 6 feet were estimated on the south shore of St, Croix and 4 feet on the north shore... For Puerto Rico, estimates ranged from 4 to 8 feet on the northeast coast and 3 to 6 feet on the southeast coast with the maximum value of 8 feet occurring at Luquillo Beach on the northeast coast. Storm surge values of 7 to 8 feet probably occurred on the island communities of Vieques and Culebra..."
Finally...here are some of my own images illustrating the severity of damage in Luquillo. These were taken as we were surveying the area surrounding our location, during the eye.
Numerous leeward facing windows, even in the center of the building on lower levels, were ripped (inclusive of their frames) out of the concrete, after interior walls failed.
The second floor of this home was completely intact prior to our chase team going into the stairwell in the video. So sometime between that point and the arrival of the eye this home was destroyed. The peak winds during the eyewall probably occurred while we were in the stairwell, as evidenced by the incredibly high-pitched wailing attending the one gust that you can hear at 0:17:15 in my video, easily the strongest gust I recall during the entire event.
As a separate perspective... although the damage is dramatic looking, this flimsy wood-frame constructed home actually fell apart in winds of 90-95kts. That said, this happened long before the arrival of the eyewall.
In conclusion I just want to reiterate that the five team members on the Hugo chase comprised some of, if not, the most experienced hurricane chasers at that time. Prior to Hugo, I already had numerous field interceptions including Hurricanes Elena, Gloria, Kate, Bonnie and Gilbert ...not to mention several of my colleagues who, by that time, had nearly 30 years of experience, each! Certainly enough familiarity with tropical cyclones of all intensities that we will all stand firmly by our assertion that Hugo was indeed of Category Four intensity at landfall in Puerto Rico, and that those extreme winds did impact coastal areas from Fajardo to Rio Grande, including my location at Luquillo.
Michael Laca
Tropmet.com
http://www.tropmet.com
It's good to hear from your perspective on this, since you were there when Hugo hit.
Footage from St. Croix during the peak of Hugo would potentially be amazing. However, given that the majority of Hugo's peak on St. Croix would have been during the night, even if there is video it might not be all that clear what's going on. My Hurricane Andrew footage (
