The tornado came without any sign—the sky was blue and the sun had been out. The first alert (警报) that my husband, Jimmy, 67, and I, 65,   got came around 9 p. m., from some scrolling text on the TV Jimmy was watching. He ran upstairs to find me in our third-floor bedroom, and we changed the channel to our local station of Pensacola, Florida.

No sooner had we found coverage of the tornado than it was on top of us. The bones of the house shook, and the power went out. The wind began to roar through the house. We had three flights of steps to move to the relative safety of the first floor. Because the closet down there is wedged (将……塞进) underneath a brick staircase, it seemed like the sturdiest (坚固的) place in our town house to wait things out.

I didn’t know how or if we would make it down the steps. It felt as if there were no floor underneath me as the wind lifted me off my feet. I gripped (紧抓) the banister (楼梯的扶手) and tried to move forwards, but this intense pressure held me in place. In those seconds of stillness, I could hear everything around me rattling (发出咔嗒咔嗒的声音).

As we reached the last flight of steps, our front door blew out. Shards of glass that looked like broken ice flew everywhere. Suddenly, a three-foot-long tree branch whipped through the door frame. It flew over our heads, missing us by inches. Had we been one step up, it would have impaled (刺穿) us. The back wall of the house followed suit and was tore off into the darkness outside.

Instantly I reached the closet, Jimmy pushed me down to the closet floor, but he couldn’t get inside himself because of the wind. I gripped Jimmy’s arm as the tornado sucked the door open and tried to bring Jimmy with it. My knees and scalp (头皮) were full of glass, but in that moment, I felt no pain. If I had let go, Jimmy would have flown right out and into the bay. “Hold on! Hold on!” he shouted. But there was nothing in this closet to hold on to.

All of a sudden, Jimmy lifted off his feet like people in tornadoes do in the movies. I thought he was gone. And then everything stopped. He landed on his feet. In those first quiet moments, I couldn’t believe it was over. Jimmy said he’d go outside to check. “No,” I said. “Don’t leave me.”

Our neighbour says the storm lasted four minutes. In that time, four of the twelve town houses in our unit were completely destroyed. Of the houses left standing, ours suffered the most damage. Amazingly, none of us were severely injured.

After a relaxing July day at the Jersey Shore in 2021, Jessica Reeder and her two children headed home to Philadelphia. As they reached Pennsylvania, they were greeted with a yellow-gray sky. It reminded Reeder of what she often saw in Southern California in her childhood when wildfires were burning.

In North America, most large wildfires occur in the western states and Canada. But smoke generated in the West doesn’t stay there. It tends to travel east. Within days, it can dirty the air in the Midwest and even East Coast towns. Today, most asthma (哮喘)-related US deaths and emergency-room visits from wildfire smoke occur in eastern cities.

The big problem comes from tiny aerosols (气溶胶) ― bits of ash, and other droplets in the air. Scientists refer to this mix as particulate matter, or PM.

The smaller the PM is, the longer it can stay in the air. And the longer it floats, the farther it can travel. The especially worrisome sizes are known as PM2.5. These bits are no more than 2.5 micrometers wide. That’s about one-thirtieth the width of a human hair. These aerosols are so small that they can be breathed deeply into the lungs. PM2.5 has been linked with breathing-related injury and heart disease.

Over the last few decades, US clean-air laws have set limits on emissions (排放) of PM from industrial sources. That has helped clean the air in many cities. But these rules don’t cover PM from wildfire smoke. Recent studies have shown that aerosols from wildfires may be more poisonous than industrial sources of these pollutants.

So far, much of the science on how wildfire PM2.5 can sicken people has focused on people exposed to smoke near fires in the US West. Now, researchers are turning their attention to how this smoke may be affecting people as far away as the East Coast. With climate change increasing the intensity and frequency of wildfires, people across North America need to be more concerned about the health impacts of this smoke.

In the second half of each year, many powerful storms are born in the tropical Atlantic and Caribbean seas. Of these, only about half a dozen becomes the strong, circling winds of 75 miles per hour or more that are called hurricanes, and several usually make their way to the coast. There they cause millions of dollars of damage, and bring death to large numbers of people.

The great storms that hit the coast start as soft circling wind hundreds—even thousands—of miles out to sea. As they travel aimlessly over water warmed by the summer sun, they are carried westward by the southeast winds. When conditions are just right, warm, moist air flows in at the bottom of such a wind, moves upward through it and comes out at the top. In the process, the moisture in this warm air produces rain, and with it the heat is changed to energy in the form of strong winds. As the heat increases, the young hurricane begins to move in a counter－clockwise motion.

The life of a hurricane is only about nine days, but it contains almost more power than we can imagine. The energy in the heat released by a hurricane’s rainfall in a single day would satisfy the entire electrical needs of the United States for more than six months. Water, not wind, is the main source of death and destruction in a hurricane. A typical hurricane brings 6 to 12 inch downpours, causing sudden floods. Worst of all is the powerful movement of the sea — the mountains of water moving toward the hurricane center. The water level rises as much as 15 feet above normal as it moves toward shore.