Challenges of Acquiring Aerial Imagery after a Hurricane


There are many offices within NOAA that are called to action during hurricane season. You may have heard of some of them, such as the National Hurricane Center and the National Weather Service, but there are other lesser known offices that provide valuable support after natural disasters such as hurricanes. One of these offices is the National Geodetic Survey (NGS). I want to talk about NGS’ emergency response role and some of the challenges that are faced while acquiring aerial imagery after natural disasters.

NGS has a history of acquiring aerial imagery to support emergency response efforts since the 1960’s (Figure 1).  At that time, imagery was acquired using traditional film mapping cameras which could take a week or more to get a final printed image. This process changed in 2003 when NGS purchased its first medium format digital camera. What used to take a week then took a day, and as technology has advanced, now takes hours. Additionally, NGS now has the capability to collect imagery from a side view (oblique) along with imagery taken with the camera pointing straight down (nadir). NGS has provided imagery after earthquakes, tornadoes, hurricanes, and severe flooding events. For the purpose of this post, I will be focusing on response efforts post hurricane.

Figure 1. A) Anchorage, AK after the Good Friday Earthquake (1963) B) Gulfport, MS after Hurricane Camille (1969) C) Aransas Pass, TX after Hurricane Celia (1970)

The decision to acquire imagery is more formal than in the past. I won’t bore you with the details other than to say that a bunch of signatures from FEMA and NGS leadership are required to make the magic happen. After it has been decided that NGS will provide imagery, flight lines for damage assessment are developed and shared with interagency partners through FEMA coordination that include state and local representation. These flight lines cover areas of potential impacts to navigation, critical infrastructure including those with potential HAZMAT issues, coastal zone management concerns, and overlapping requirements of federal partners including FEMA, USCG, USACE, NGA, and USGS to prevent duplication of effort.

The plane, sensors, and personnel are prepositioned to a safe staging area before the hurricane makes landfall (Figure 2). Imagery acquisition starts as soon as the hurricane passes the area and conditions are safe to fly. NGS faces a number of challenges everytime they set out to collect imagery because, just like every hurricane is different, so is the response. Sometimes they can get ahead of issues that pop-up, while other times they have to think quickly and change the plan on-the-fly.

Figure 2. Two Trimble medium format digital cameras are installed on the NOAA King Air to collect imagery to support emergency response.

Weather is the biggest challenge and really drives the type of imagery (nadir or oblique) and what areas are acquired. This is one of the reasons why they don’t make daily flightlines available. The goal is to acquire imagery every day even if that means changing the order of the priority areas. This was certainly the case when they were acquiring imagery post Hurricane Irma over the Florida keys. They acquired imagery of the Key West area on Sept 11. They then planned on collecting imagery the next day of Sugarloaf, Big Pine and Cudjoe keys before moving on to Marathon. Unfortunately, due to adverse weather conditions (clouds), and other aircraft (search and rescue) that took priority, they had to quickly change the plan. Fortunately, they were able to get imagery for the Big Pine and adjacent areas on Sept 13. They were disappointed that it took a little longer to get imagery for the area but they did the best they could given the circumstances.

Hurricane Maria presented them with a new challenge that they had previously not faced since collecting imagery with a digital camera. They had to acquire imagery with a plane over an island that had no power, no functioning airport, and no place on the island to set up a home base.  The closest place that would support the necessary requirements for fuel and data processing was Curacao, a sovereign state of the Netherlands.  They based out of Curaco for  part of the Maria response flying to Puerto Rico (and then back to Curaco), post processing imagery, and uploading it to create the Hurricane Maria website. (Figure 3)

Figure 3.  Pink line represents the flight path of the airplane during an image acquisition day following Hurricane Maria

The 2017 Atlantic hurricane season was deadly, destructive, costly, and just really horrible all the way around.  Since August 27, 2017 NGS collected close to 65,000 images, covered over 24,000 sq km, and utilized 195 flight hours in response to Hurricanes Harvey, Irma, and Maria. The imagery was used to assist in the opening of ports, the identification of marine debris, and by folks in the impacted areas to assess the condition of their home.  I’m glad we made it through the 2017 Atlantic hurricane season and hope that we don’t see another one like it for many years to come.

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