Describe a hurricane as completely as you can by giving typical values for the following characteristics: diameter, location and size of the eye, direction of rotation and speed of winds, central pressure, direction and speed of movement, and duration. When and where do hurricanes form?

Question

What will be the ideal response?

Answer 1

ANSWER: A hurricane is an intense storm of tropical origin, with sustained winds of at least 64 knots (74 mi/hr) and with considerably higher gusts, that forms over the warm northern Atlantic and eastern North Pacific oceans. On average, a hurricane’s thickest clouds cover an area of approximately 500 km (310 mi) in diameter. The relatively clear area at the center is the eye. The eye is around 40 km (25 mi) wide. Within the eye, winds are light and clouds are mainly broken. The surface air pressure is very low, around 955 mb (28.20 in). Clouds align themselves into spiraling bands (called spiral rain bands) that swirl in toward the storm’s center, where they wrap themselves around the eye. Surface winds increase in speed as they blow counterclockwise and inward toward this center. (In the Southern Hemisphere, the winds blow clockwise around the center.) Adjacent to the eye is the eyewall, a ring of intense thunderstorms that whirl around the storm’s center and may extend upward to almost 18 km (59,000 ft) above sea level. Within the eyewall, we find the heaviest precipitation and the strongest winds, which are on the order of 105 knots (121 mi/hr), with peak gusts of around 120 knots (138 mi/hr). As we approach the hurricane from the west, the sky becomes overcast with cirrostratus clouds; barometric pressure drops slowly at first, then more rapidly as we move closer to the center. The high winds, which generate huge waves over 10 m (33 ft) high, are accompanied by heavy rainshowers. As we move into the eye, the winds slacken, rainfall ceases, and the sky brightens, as middle and high clouds appear overhead. The atmospheric pressure is now at its lowest point (965 mb), some 50 mb lower than the pressure measured on the outskirts of the storm. The brief respite ends as we enter the eastern region of the eyewall. Here, we are greeted by heavy rain and strong southerly winds. As we move away from the eyewall, the pressure rises, the winds diminish, the heavy rain lets up, and eventually the sky begins to clear.