The most powerful hurricane to hit the US in fourteen years blasted ashore in Texas on August 25, 2017 — and that was just the start of the trouble. Now, another hurricane threatens the Caribbean Islands and the southeast US.
The solar eclipse lived up to its billing, and many are planning for the next one — in 2024.
And southern Europe will be happy to see the blistering summer of 2017 fade into fall.
Let’s go Around The World.
Harvey: First Wild Wind, Then Relentless Rain
Hurricane Harvey howled ashore near Victoria, Texas in the evening hours of August 25, 2017 with 140 mile per hour winds. Within 18 hours, Harvey’s designation cascaded downward through three hurricane categories and into Tropical Storm status.
But, unlike most hurricanes, Harvey wasn’t finished devastating places in its path, even after it had been significantly downgraded. That’s because its path was pretty much in the same place for several days.
As Harvey headed northwest and picked up steam (figuratively and literally) over the warm Gulf of Mexico, high pressure built over the plains and blocked its movement. The result was an enormous amount of rain for southeast Texas.
The atmospheric mechanics were not difficult to understand, and forecasters had predicted the rain would add up to unprecedented totals many days before the hurricane made landfall.
Normally, there is little interaction between the weather of the tropics and that of mid-latitudes. The former is dominated by easterlies, while west winds predominate in the latter. Between the two zones, high pressure dominates in a circle near 30 degrees latitude in both hemispheres. Occasionally a cold front pushes south into the subtropics, and, more frequently, a tropical system interacts with the westerlies at higher latitudes.
Normally the tropical system is picked up and drawn northward by the jet stream. But in the case of Harvey, the path was blocked by high pressure and the storm (what was left of it) stalled near the Texas coast. Though the wind had nearly dissipated, massive amounts of moisture were still present. So it rained — and it rained.
As of now, 44 deaths have been attributed to Harvey, most by drowning, and much of southeast Texas is still under water.
What Makes A Flood?
Flooding is not hard to understand: water in, water out. Rainfall drains through natural outlets (rivers and streams) and man-made ones (sewers and spillways). If water in is greater than water out, the water rises. Eventually it can flood streets and houses.
Whenever there’s a once-in-a-(hundred/500/thousand) year storm, I like to tell one of my favorite jokes. If you’ve heard it before, you can skip down to Irma.
A man comes into a bar and announces, “Better clear out, Big John’s a-comin’,” but before the patrons can leave a giant of a man strides through the door, comes to the bar, and orders a fifth of whiskey. As the customers cower, the bartender places a bottle on the bar. The huge man downs it in a single chug and orders another.
As the bartender serves the second bottle, he gets up his nerve to stammer, “Wh-what’s the r-rush, mister?”
And the giant answers, “Ain’t ya heard? Big John’s a-comin’.”
Harvey has been judged by some experts to be a thousand-year rain event. Certainly 50 inches of rain in Houston in ONE WEEK — more than the 49 plus ANNUAL average — is an infrequent occurrence. But was Harvey the worst a storm could be? Was it Big John?
Consider what would have happened if Harvey had stalled just offshore instead of inland. 140 mile per hour winds would have blasted the same area for days, rather than hours — along with the rain. So nobody really knows how big ‘Big John’ will be.
And Here Comes Irma
Hurricane Irma has taken advantage of favorable conditions across the Atlantic Ocean (light wind shear and warm water) to strengthen into a major hurricane, with 150 mile per hour winds at last report.
Though it is too early to make a forecast for eventual landfall in the US, the storm will hit the Leeward Islands hard. After that, Irma will affect Puerto Rico, Hispaniola, and Cuba.
It is hard to see how the storm could avoid striking land either on the east coast of the US or somewhere in the eastern Gulf of Mexico.
Irma is the ninth named storm of the season, which is only half over.
Lucifer: The Heatwave From Hell
Southern Europe baked under one of its hottest summers ever. Heat Wave Lucifer, which peaked in early August, is now gone, giving in to the inevitable change of seasons. But not until five people died from the heat.
The heat in Spain was relentless all summer, with the national all-time record falling on July 13, 2017 when the mercury climbed to 46.9° C (116.4° F) at Córdoba airport.
Alpine skiing events, normally possible even in midsummer, were canceled due to the slushy conditions.
US Not Immune To Record Heat
Parts of the US west have had summer temperatures rarely seen — and a few never seen. The mercury spiked over 100° F in normally-cool Seattle, Washington and Portland, Oregon. In Utah, Salt Lake City had its hottest July on record.
The cause of the western US heat was a stagnant high pressure system that persisted the entire summer. The evidence is anecdotal, but persistent patterns appear to have become more pronounced with global warming: heat waves, stalled tropical storms, and ‘training’ thunderstorms (lines of storms traversing the same path).
Many millions of people watched the total solar eclipse of August 21, 2017 with awe. It was a time to contemplate the mysteries of the universe, which man has barely begun to understand. It was a moment (just 2 minutes in most places, and that was in a narrow path less than 100 miles wide) of unusual harmony in a turbulent world.
Today, things seem back to normal, but one can hope that the stunning spectacle had a cathartic effect on the natural curmudgeonliness of man.