The sky can take on various colors before a hurricane due to the complex weather dynamics involved. While a darkening sky is most commonly associated with an approaching hurricane, the exact color depends on factors like cloud cover, humidity, and time of day. Understanding sky color changes can help alert communities that a hurricane is near.
Typical Sky Colors Before a Hurricane
The most common sky colors observed before a hurricane are:
| Dark gray | As thick storm clouds roll in, they can make the sky appear dark gray or charcoal-colored. This is due to the dense cloud cover blocking sunlight. |
| Slate gray | Thick clouds mixed with rain can also make the sky look slate gray or steel-colored. |
| Greenish | The sky may take on a dark greenish hue due to sunlight filtering through moisture-laden air. |
| Yellowish | At times, the sky appears brownish-yellow as dust and sand swirl in the strong winds around a hurricane. |
These ominous colors signify a hurricane is likely within a day or two of impact. The thickening clouds are the leading edge of the storm.
Why Does the Sky Change Color?
There are several reasons why the sky takes on such dark, ominous colors before a hurricane:
– Thick Cloud Cover – The dense, tall clouds of a hurricane simply block sunlight from reaching the ground. With less direct sunlight, the sky darkens.
– Rain and Humidity – The thick, moisture-laden air caused by heavy rain and humidity scatters light differently, leading to grey, greenish, or yellowish hues.
– Sand and Dust – Powerful hurricane winds stir up sand, dirt, and debris, which further limits sunlight penetration and creates a murky, yellowish color.
– Time of Day – In the early morning or late afternoon, the sun sits at a lower angle, causing sunlight to pass through more atmosphere. This leads to more light scattering and muted, darker colors.
– Storm Structure – The shape, density, and height of storm clouds and the exact mix of rain, dust, and humidity all impact the final sky color. No two hurricanes are exactly alike.
In short, the combination of thick storm clouds, heavy rain, increased humidity, and strong winds all contribute to creating darker stormy skies as a hurricane approaches.
Reading the Sky Colors
Learning to read the sky colors can serve as an early warning that a hurricane is approaching or strengthening.
– Dark gray skies in the morning can signal a hurricane is coming within the next 12-24 hours.
– Slate gray skies that continue darkening throughout the day suggest a storm is intensifying and winds are picking up.
– Greenish or yellowish hues early in the day indicate moist tropical air and likely hurricane conditions within 36 hours.
– Light green skies in the evening mean a hurricane is very near, while dark green at sunset suggests the storm’s outer rain bands are overhead.
Being able to interpret these colors gives people more time to complete protective measures before a hurricane arrives. Looking at cloud patterns and observing wind shifts can add to forecasting a storm’s onset.
Before and After Comparison
It’s helpful to compare normal sunny sky conditions to the typical hurricane sky:
| Normal Sky | Hurricane Sky |
|---|---|
| Bright blue | Dark gray |
| Crisp white clouds | Thick gray clouds |
| Clear light | Diffuse light through moisture |
The contrast shows how markedly different a sky appears when an area transitions from calm to pre-hurricane conditions. Clouds thicken and lower while the sky loses its vibrant blue hue.
Other Weather Clues
While sky color is a useful hurricane indicator, other weather signs can also help predict if a storm is nearing:
– Powerful lightning off the coast signals conditions right for hurricane development.
– Bands of rain sweeping in from the ocean often precede a hurricane by a day or so.
– Swirling gusty winds indicate the storm’s circulation is expanding over the area.
– Atop tall buildings, veering winds switching from easterly to southerly suggest a hurricane’s approach from the south.
– Barometric pressure readings steadily falling warn a hurricane is advancing.
– Tide levels rapidly rising alert that a storm surge is imminent.
Combining these weather clues with monitoring the sky gives the most complete hurricane alert.
Conclusion
In the day or two before hurricane impact, the sky takes on various darker hues of gray, green, or yellow compared to normal conditions. The thickening cloud cover, increasing humidity, and interaction of sunlight through moisture laden air all contribute to creating darker stormy skies. Recognizing these color changes allows extra time to respond before a hurricane arrives. While sky colors serve as useful visual alerts, other weather signs like winds, rains, and pressure should be monitored as well. Paying attention to the sky and surrounding conditions provides the most effective early warning that a hurricane is nearing.
