A man cleans a car during the snowstorm in Washington on Sunday. (Brendan Smialowski/AFP/Getty Images)

It’s snowing as I write this — early on Sunday morning — but who knows what the weather will be like when you read it. Maybe a warm snap and a cleansing rain will have come to melt all the snow, and this column won’t make sense.

“ ‘Clear the snow off the roof of your car, you moron’?” you’ll ask yourself. “What does he mean by that? There’s no snow.”

Don’t play coy. You know exactly what I mean. Every time it snows around here, we’re treated to people who think it’s acceptable to get their motors running, head out on the highway, looking for adventure and whatever comes their way . . . without sweeping that massive rectangular lozenge of snow from the roof of their vehicle.

What often comes their way — well, not their way but the way of the vehicles behind them — is a dense sheet of snow, sailing through the air like a gelid missile.

Extreme weather of any sort brings out the bad drivers — or, rather, allows the bad drivers to reveal themselves. I have a feeling that the people who don’t use their turn signals are the same ones who don’t put their headlights on in the rain. And who, after an ice storm or snowstorm, clear a tiny patch on their front windshield, a tiny patch on their rear windshield — and that’s it.

A snow-topped car always reminds me of the hairstyle on Kid from the rap duo Kid ’n Play, but instead of a column of hair it’s a mattress of snow. (Improperly secured mattresses are another of my obsessions, but that’s a column for another day.)

Please, when it snows, clean off your entire car. Use a broom to get the roof, or open a door, stand on your vehicle’s sill and sweep your arm back and forth. At least make the effort.

Water woes

I am reliably informed that snowflakes are just water drops that have gone to finishing school. And yet I hate water so much more than I hate snow.

Last week, I wrote about a pesky water leak that’s coming from an upstairs shower and bespoiling our living room ceiling. Many readers shared their own sad stories. The NTSB has nothing on those of us who have to painstakingly track down the cause of our watery woes.

Michael Lipsky of Vienna, Va., had a shower leak, the cause of which was finally traced to the shower head. When it was new, it turned easily on a lubricated fitting. As it got older, it became harder to turn.

“The pressure we exerted to turn the shower head away from us as we got into the shower transferred to the vertical pipe behind the tiles,” Michael wrote. “Repetitive pressure on the pipe behind the tiles after 13 years eventually caused the pipe fitting to break, resulting in the leak we experienced this past summer.”

For Richard Ehrenreich of Olney, Md., the problem was behind the tiles. After “everyone short of the Pope” had been out to try to trace Richard’s leak, someone finally realized that regular wall board, not water-resistant wall board, had been used.

“That soaked up water from pinhole openings in the grout and eventually became saturated,” Richard wrote. “As the access to the soaked wall board continued, the trickle of water turned into a creek, then a river, but we fixed it before it became an ocean.”

Lois Dyer lives in the District’s Crestwood neighborhood. A plumber said her leak was water coming from the roof. A roofer said it was a plumbing problem or a brick-mortar problem. A home inspector finally diagnosed a cracked shower pan.

The District’s Jonathan Rickert had a similar problem in his late-1930s-era home. “Long story short, we eventually redid the whole bathroom and had the tile-over-concrete floor ripped out. Our contractor found pinhole leaks in the copper pipe embedded in the concrete. Since that pipe has been replaced, over 15 years ago, no more leaks.”

Colin Scott of Alexandria, Va., endured years of misdiagnosis and patch-up jobs before finally biting the bullet. The culprit? A hole in the rubber skirt under the shower. Wrote Colin: “It’s an archaic system anyway and the rebuild with a different design is watertight so far!”

Joel Kelty, an architect who lives on Capitol Hill, wrote: “You might consider overlaying the tile with a thin sheet of solid surface material such as Corian rather than tearing out the tile.”

Ron Kalimon of Silver Spring, Md., had the only surefire solution: “Level the house down to the foundation and rebuild. That should do it.”

Thanks, Ron.

We’ve decided to caulk the bejesus out of our shower, especially the corner that had visible cracks. It should be dry by Tuesday when we’ll perform some tests. Light a candle for me.

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/john-kelly.