The supplemental information section in the state regulations details the plan requirements for documenting the Facility Descriptions and Operational Overview. State of Alaska regulations relative to this topic are not addressed in this section of the SEAPRO Technical Manual. Instead, this section will provide basic information about SEAPRO, its member companies and resources for aiding in the development of a Response Plan.
The area of Alaska covered by SEAPRO for spill response activities falls under the Southeast Captain of the Port Zone covering Southeast Alaska from Dixon Entrance to Yakutat. A copy of the zone map can be downloaded by clicking the link.
The area described as Southeast Alaska is a thirty mile-wide strip of mainland, bordered by an eighty mile-wide compact chain of islands. It is approximately 250 miles long, with close to 11,000 miles of shoreline. Because of the nature of the landscape, there is little, if any, roaded access between or among communities; travel takes place by water or air. The SEAPRO region of operations extends from Dixon Entrance in the south to Yakutat in the north, with the Coast Mountains and the Pacific Ocean its east and west boundaries. It is an area known for its beauty, varied and rich historical heritage and abundant wildlife. While the entire region of Southeast Alaska is considered environmentally sensitive, there are certain areas considered the “Most Environmentally Sensitive Areas” (MESAs). A map and list of the eleven (11) MESAs in Southeast Alaska appear in this section. (A detailed description of each MESA and appropriate protection strategies is provided at the Prevention and Emergency Response General Description of Maps by zone of occurrence.)
SEAPRO’s operational area is generally an area of densely forested (predominately Sitka spruce and western hemlock), glacier-ridden mountains and water. The advance and retreat of glaciers has left the area with hundreds of miles of intricately carved, tree-lined shores which consist of bays, channels, estuaries, tideflats and fjords. Virtually all of the communities (sixteen organized communities with a total population of about 73,000¹ people) are located on the shoreline.
The Tongass National Forest Wilderness region encompasses the majority of Southeast Alaska. Within this national forest there are many smaller parks, wilderness and refuge areas. The forest areas are important to Southeast Alaska’s economy, as they provide timber resources, fish spawning grounds, wildlife habitat, recreational land and tourist attractions.
The State of Alaska, Alaska Geo-Spatial Data Clearinghouse provides maps and information related to the Most Environmentally Sensitive Areas identified throughout Alaska. The insert below provides access to this information.
Southeast Alaska is a region of intricate and complex shorelines, ranging from steep, rocky cliffs to broad soft tideflats in the bays and coves. Most shorelines, however, are composed of a mixture of sand, gravel and boulders. The more protected areas consist of fine gravel and sand, while shorelines exposed to more wave action consist of boulders and cobbles. Forests commonly extend from sea level to 3000’ in the southern part of the region and to 1800’ further north. These dense forests are interrupted by muskeg bogs, delta marshes and glacial plains, and river valleys. Refer to the Environmental Sensitivity Index for definitions of the various shoreline types and recommended shoreline countermeasures and response strategies. Refer to Seasonality Tables for a listing of wildlife species found in Southeast Alaska and their critical life periods. Refer to Geographic Response Strategies (GRS) for wildlife response strategies.
Tideflats are found in the most protected areas and are comprised of fine sand and silt. The largest tideflats in Southeast Alaska are located at the Stikine Delta and Mendenhall River Flats. Eelgrass is common vegetation found growing in tideflat areas, providing unique habitat for diverse groups of organisms. The eelgrass itself, as well as the organisms it supports, provides food for migrating waterfowl and shorebirds, nursery areas for Dungeness crab and spawning substrate for herring. Shrimp, mollusks and other crustaceans are abundant in tideflat zones.
Tidal marshes are a transitional zone between the estuarine and upland environments. Some of the most extensive tidal marshes in Southeast Alaska are located at the Stikine Flats. Terrestrial mammals (i.e., deer, mink) feed here at low tide, while marine animals utilize the marshes at high tide. Bear and eagles frequent tidal marshes when they feed on spawned-out salmon. Salmon fry also feed in tidal marsh areas.
The ShoreZone mapping system has been in use since the early 1980s and has been applied to more than 40,000 km of shoreline in Washington and British Columbia (Berry et al 2004; Howes 2001). Through partnerships with other agencies and organizations, portions of southeastern and central Alaska have been imaged and mapped. This project is funded by NOAA and a number of other agencies and organizations as listed below.
This standardized system catalogs both geomorphic and biological resources at mapping scales of better than 1:10,000. The high resolution, attribute rich dataset is a useful tool for extrapolation of site data over broad spatial ranges and creating a variety of habitat models.
Low-tide-oblique aerial imagery sets this system apart from other mapping efforts. You can "fly the coastline" (video), view still photos, and access biophysical data using our interactive ArcIMS web-site. This site will include more of Alaska's coast-line as new data becomes available.
For a tutorial on how to use the Alaska ShoreZone Coastal Mapping and Imagery click here
The maritime climate of Southeast Alaska is highly influenced by local topography which affects precipitation, winds and sea movement. The information to follow is an overview of tide, current , wind, precipitation, visibility, temperature and ice conditions in Southeast Alaska. For more detailed climatic information for each zone, see Southeast Alaska Weather, bearing in mind that historical data is simply not available for some regions in Southeast. In the latter cases, area-specific information must be obtained from local residents.
The Alaska Current circulates in a counter-clockwise course in the Gulf of Alaska. However, tidal currents, winds and fresh water runoff can exert significant effects on net surface currents in many areas.
Seas along the inside route are generally calmer than those along the outside sea routes; wave heights of five feet (5’) or less are experienced fifty percent (50%) of the time or less, compared to fifteen feet (15') at sea. Swells are experienced in the straits only when its direction is in line with the entrance. Outside wave heights of twelve feet (12’) or more occur about twenty five percent (25%) of the time.
In Southeast Alaska, daily fluctuations of salt water tides are usual, creating powerful tidal currents. Examples of the area’s diurnal tide range are: Sitka - 9.9’; Ketchikan - 15.4’ and Haines - 16.8’. A normal high tide, however, will be influenced by 1’ or more when combined with strong, offshore winds accompanying storms. Although tidally induced currents are factors in determining net surface currents, tidal currents are not usually considered important in long distance transport since they are oscillatory in nature. The additional variables of wind and freshwater runoff, however, must be taken into account. In some cases, tidal currents will be counteracted by these variables and will not be the deciding factor in spill transport. In addition, tidal currents can be difficult to predict in some areas due to flood tide entering the region’s many north-to-south straits and passages from both ends. This has been documented to occur in Chatham Strait, according to the Southeast Subarea Contingency Plan. Illustrations of some of the current patterns in Southeast Alaska can be found in pages E-12 to E-22 of the Southeast Subarea Contingency Plan.
Current and future Alaska Tide Tables are available here.
Winds in Southeast Alaska are almost constant, ranging from light winds in protected valleys to strong winds along the coast and at high elevations. Local topography will affect wind patterns; wind speeds may at times increase drastically as the air currents are funneled through narrow valleys/channels.
Along the outside sea routes, wind speeds of thirty-four knots (34 kts) or more are experienced about ten percent (10%) of the time, often from the southeast or south. Average wind speeds are 20-22 knots. Most inside routes experience southerly or southeasterly winds, with wind speeds that vary from 3-4 knots to 13-15 knots (or more during the winter).
Average annual precipitation for Southeast Alaska varies from 80” to more than 200”. The percentage of days with measurable precipitation is highest along the inside coast from Ketchikan to Juneau. That percentage decreases along the outside coastline and is the lowest within the inner northern channels. September, October and November are the wettest months in most locations. May, June and July are generally the driest months.
Snowfall may total 30" - 200” in more populated areas and 400” in the higher elevations. Snow at the lower elevations, however, may last only a few days due to extensive rainfall and temperature fluctuations.
Long periods of cloudy or overcast skies are fairly constant in Southeast Alaska (approximately 50% of the time). Fog occurs year-round, but is heaviest in the late summer and early winter. In general, visibility 5 miles or less occurs 80-85% of the time. Reduced visibility is an important consideration with regard to response efforts, because it could preclude flight operations and visual observations of a slick as well as booming and skimming vessel efficiency. Limitations for flight surveillance operations based on visual flight rules for rotary and fixed-wing aircraft are:
For booming and skimming vessels, the visibility limitation varies between 0.125 nautical mile (200 meters) and .5 nautical mile (800 meters), depending on temperature, sea state, wind and precipitation.
The maritime influence of the area creates cool summers and mild winters. In the summer, temperatures are generally warmer inland than on the coast. The opposite is true in the winter months. While temperature ranges for most places in Southeast Alaska are not extreme (averaging 50°- 60°F in July to 20°- 40°F in January), during a spill response effort, wind chill has more impact on worker safety and equipment efficiency than temperature. Wind chill indices that combine temperature, wind and length of exposure can be used by responders to determine the amount of time it is safe to work and the amount of time needed to recover from the effects of wind chill. It should be noted that the danger area would seldom be reached. A chart illustrating the effect can be found at Wind Chill Factor. You can also access a Wind Chill Calculator by clicking here.
Southeast Alaska is relatively free of sea ice; however, chunks of glacial ice may be encountered (most frequently near the mouths of certain inlets). Occasional strong winds at some of these narrow inlet locations, perhaps accompanied by blinding snow storms, can impact ice conditions which will, in turn, make oil spill cleanup operations more difficult. Fortunately, these conditions occur infrequently, in addition to which, the areas where glacial ice may be encountered are not found on regular oil barge routes.
As described in the Southeast Subarea Contingency Plan, ice originating in Glacier Bay can create navigational hazards in the Icy Strait/Cross Sound area. Considerable ice can also be present in Icy and Yakutat Bays. Ice originating in Endicott Arm and Tracey Arm may create similar problems in Holkan Bay and adjacent portions of Stevens Passage, while ice originating in LeConte Bay is carried northerly past Horn Cliff in Frederick Sound.
Southeast Alaska is one segment of an active seismic belt that rims a large part of the Pacific Ocean; some of the region’s “narrows” and “channels” were created by the seismic activity of this fault system. Because many of these faults are at great depths, there is a greater likelihood of ground shaking than surface ruptures. A major quake in Southeast could create tsunamis. As these waves approach shore, they slow and dramatically increase in height. Moving across open seas at rates up to 500 miles per hour, these tremendous waves can affect the entire region, most notably, those areas nearer open water. Communities along the inside waterways of Southeast Alaska, however, would be more likely to encounter damage from “seiche wave”¹ run-up than tsunamis.
SEAPRO’s area of operations, from Dixon Entrance to Yakutat, matches the area of responsibility for the USCG MSO Juneau Marine Inspection and Captain of the Port Zone (33 CFR 3.85-10). It is identified in Alaska statutes as the “Southeast Region” and is also one of the ten federal planning regions in the State for the federal government. The State of Alaska along with a number of various federal agencies have prepared a Unified Plan for the entire state of which the Southeast Subarea Contingency Plan for this region is a part. Although the Subarea Plan is currently being updated, SEAPRO has nevertheless included some of the information contained in that Plan in this Technical Manual because many SEAPRO members do not have access to the Subarea Plan.
For purposes of response planning and management for the large and diverse geographical area covered by the SEAPRO cooperative, SEAPRO has divided its area of operations (defined above) into the 9 zones listed below and illustrated on the following page. The zone boundaries were arrived at based on statutory requirements for SEAPRO to meet the 12-hour criteria established for an OSRO Inland/Near Shore Tier 1 facility response and a 24-hour vessel response. State regulations require a spill to be contained and controlled within 48 hours and cleaned up in the shortest time possible. The center of each zone is one of the larger communities in Southeast wherein most SEAPRO facilities are located.
| Zone | Cities |
|---|---|
| 1 | Ketchikan/Metlakatla |
| 2 | Craig/Klawock/Hydaburg |
| 3 | Wrangell/Petersburg |
| 4 | Kake |
| 5 | Sitka |
| 6 | Pelican/Elfin Cove/Gustavus |
| 7 | Juneau |
| 8 | Haines/Skagway |
| 9 | Yakutat |
Click here to display the SEAPRO Zone Map.
SEAPRO member companies vary from fish processors and logging operations to bulk fuel storage facilities and barge operations (click here to see the list of member companies). SEAPRO has four (4) categories of membership: