Hail - Precipitation in the form of lumps of ice, mainly associated with thunderstorms. Hail size usually ranges from that of a small pea to the size of cherries, but has been observed as large as oranges. Hail in Canada occurs most frequently during the summer when thunderstorm activity is at a peak. Extensive damage in the agricultural industry is caused each year by hailstorms.
Category: - Weather

Halo - In ages past, the huge rings or haloes around the sun or the moon were thought to portend everything from storms to great personal disasters. We now know that they are the optical result of the refraction of light from the sun or moon by ice crystals in the very high cloud (9,000 meters) called cirrus or cirrostratus.On occasion, only two bright spots on either side of the sun can be seen. These are known as sun dogs and are caused when the ice crystals occur in a certain uniform arrangement.
Category: - Weather

Halyard - The line used to raise and lower the sail.
Category: - Maritime

Harbor Dues - Various local charges against all seagoing vessels entering a harbor, to cover maintenance of channel depths, buoys, lights, etc. all harbors do not necessarily have this charge.
Category: - Maritime

Harbourmaster - A man in charge of a harbour, authorizing entry, and arranging for Pilots to guide vessels into difficult harbours, past underwater obstructions, etc.
Category: - Maritime

Hard Aground - A vessel which has gone aground and is incapable of refloating under her own power.
Category: - Maritime - Risk

Hatch - An opening, generally rectangular, in a ship's deck affording access into the compartment below.
Category: - Maritime

Hatch Battens - Flat bars which are wedged against hatch coamings to secure tarpaulins.
Category: - Maritime

Hatch Beam - A portable beam used to support wooden hatch covers.
Category: - Maritime

Hatchway - A large covered, usually rectangular opening in a ships deck for putting and removing cargo from under the deck.
Category: - Maritime

Hawse Pipe - Casting, or castings, through deck and side of ship at bow for passage of anchor chain.
Category: - Maritime

Hawser - Large strong rope used for towing purposes and for securing or mooring ships. Hawsers are now mostly made of steel.
Category: - Maritime

Hazard - Activity task, operation, tool or agent that is a significant source of personal physical risk and potential negative consequences
Category: - Risk

Haze - Fine dust or salt particles dispersed through a portion of the atmosphere which reduce visibility. Haze is distinguished from fog by its bluish or yellowish tinge.
Category: - Weather

Heave To - To stop a boat and maintain position (with some leeway) by balancing rudder and power to prevent forward movement, a boat stopped this way is "hove to"
Category: - Maritime

Heavy Rainfall Warning - Whenever 50 mm or more of rain is expected in a 24-hour period, a heavy rainfall warning is issued.
Category: - Risk - Weather

Heavy Snowfall Warning - A warning is issued when 15 cm of snow or more is expected in a 24-hour period. It may be issued for lesser amounts at the beginning or end of the snow season.
Category: - Risk - Weather

Heeling - The inclination of a vessel to one side.
Category: - Maritime - Risk

Helm - A tiller or a wheel generally installed on the bridge or wheelhouse of a ship to turn the rudder during manoeuvering and navigation. It is in fact the steering wheel of the ship.
Category: - Maritime

Helmsman - An able-bodied seamen entrusted with the steering of a vessel.
Category: - Maritime

Hercules - The Hercules (CC-130) is the primary fixed-wing search airplane at all SAR units except 442 squadron in Comox. It is a medium lift transport airplane ideal for long-range SAR operations. Because of its large size and equally large turning radius, it is limited in the scope of its operations in mountainous terrain. Because they are also used for tactical airlift operations, the Hercules are painted either gray or camouflage. The Hercules' SAR crew consists of two Pilots, a Navigator, a Flight Engineer, a Loadmaster and two Search and Rescue Technicians.
Category: - SAR

High - In the Northern Hemisphere, an area of high atmospheric pressure with a closed, clockwise movement of air (circulation). Also known as an anticyclone.
Category: - Weather

HMCS - A prefix used before a navy vessel's name to denote that it is owned by the crown (Her Majestys Canadian Ship)
Category: - Maritime - Acronym

Hogging - Straining of the ship which tends to make the bow and stern lower than the middle portion.
Category: - Maritime

Hoist - All SAR helicopters are equipped with an external hoist, either electric or hydraulic, used to raise and lower rescuers to and from the ground or water (the Labrador also has a backup hoist which is located internally, and operates through a hole in the belly). When someone is raised or lowered on the hoist, they are "hoisted." Hoisting is always vertical. Hoisting should not be confused with winching, which involves pulling objects horizontally, as in the case of the Buffalo and Hercules which have winches to pull large loads of cargo onto the plane when on the ground or to pull the SAR Techs back in if they get caught on the side of the plane when parachuting.
Category: - Weather

Hold - A general name for the spaces below the main deck designated for stowage of general cargo. A hold on a tanker is usually just forward of #1 cargo tank. Some newer tankers have no hold.
Category: - Maritime

Hovercraft - A vessel used for the transportation of passengers and cargo riding on a cushion of air formed under it. It is very maneuverable and is also amphibious.
Category: - Maritime

Hull - The body of a ship, including shell plating, framing, decks, bulkheads.
Category: - Maritime

Humanitarian Incident - A search and rescue (SAR) incident (not aeronautical or maritime) which requires a response by the SAR system to preserve human life or relieve suffering. "incident humanitaire"
Category: - SAR

Humidity - A measure of the water vapour content of the air. Usually relative humidity is expressed as a percentage of total possible moisture content.
Category: - General

Hurricane - Also known as Typhoons, Tropical Cyclones and Willy-Willies these are tropical storms with wind speeds of 65 knots (120km/h) up to 240 knots (460 km/h) that can be thousands of square kilometers in size. Such systems usually have a lifespan of several days. In the North Atlantic, the hurricane season is from May to November, but the majority at storms occur in August, September and October. Although the east coast is the area of Canada most frequented by hurricanes, these storms still average less than one per year over the Atlantic Provinces and coastal waters. While there have been as many as five in one year, several years can pass with no tropical storms. A hurricane warning is issued in the Marine Forecast if winds are expected to exceed 64 knots (115 km/h).
Category: - Weather

Hydrofoil - A craft more or less similar to the Hovercraft insofar as it flies over water and thus eliminates friction between the water and the hull. Under acceleration it rises above water but remains in contact with the surface through supporting legs.
Category: - Maritime

Hydrography - Charting bodies of water
Category: - Maritime

Hypothesis - A tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation
Category: - Risk