Is a hard rain gonna fall?
August 8, 2022 11:06 AM Subscribe
I am trying to decide whether to drive in certain conditions and would like to know what this rain amount means to visibility.
I have a more difficult time than most people seeing/driving in hard rain.
This particular route is awful when it is a hard rain, because it is a highway with people going very high speeds in trucks no matter what, there is absolutely nowhere to pull off the road if it starts getting bad visually, there is even no shoulder (and actually I find pulling onto the shoulder dangerous when it's raining so bad that no one can even see you on the shoulder) and people in their large vehicles just seem to plough through it all while I in my small car feel unsafe.
It would be very very good for Reasons for me to make this trip tomorrow (I do not need advice on that) but it will be raining literally all day and I want to decide on whether it will be That Kind of rain.
The prediction is for 0.03 in per hour during the time I need to go.
What does that look like for driving?
When I google, some of the info says .3 inches/hour is heavy rain. Other places say .03 inches /hour is heavy.
I have a more difficult time than most people seeing/driving in hard rain.
This particular route is awful when it is a hard rain, because it is a highway with people going very high speeds in trucks no matter what, there is absolutely nowhere to pull off the road if it starts getting bad visually, there is even no shoulder (and actually I find pulling onto the shoulder dangerous when it's raining so bad that no one can even see you on the shoulder) and people in their large vehicles just seem to plough through it all while I in my small car feel unsafe.
It would be very very good for Reasons for me to make this trip tomorrow (I do not need advice on that) but it will be raining literally all day and I want to decide on whether it will be That Kind of rain.
The prediction is for 0.03 in per hour during the time I need to go.
What does that look like for driving?
When I google, some of the info says .3 inches/hour is heavy rain. Other places say .03 inches /hour is heavy.
Best answer: Meteorologist Tom Skilling classifies .03 as a "heavy drizzle" vs. .3 as "heavy rain":
Link
posted by jabes at 11:11 AM on August 8, 2022 [1 favorite]
Link
posted by jabes at 11:11 AM on August 8, 2022 [1 favorite]
Response by poster: Weather.com says between .03 and 0.04 inches per hour.
posted by ojocaliente at 11:11 AM on August 8, 2022
posted by ojocaliente at 11:11 AM on August 8, 2022
Can you pinpoint a specific date in the past where the rain was too heavy for you to drive, then look at the historical rainfall record for that day?
posted by muddgirl at 11:25 AM on August 8, 2022
posted by muddgirl at 11:25 AM on August 8, 2022
Best answer: You got it yourself with those numbers. All day's worth of drizzle would be a hard rain if it fell in an hour. Or, spreading an hour of hard rain out over a long time will change it to a drizzle
If it's actually around 0.03 in/hr you will be fine with respect to visibility. If anyone said that rate is 'hard rain', they are wrong.
posted by SaltySalticid at 11:25 AM on August 8, 2022 [1 favorite]
If it's actually around 0.03 in/hr you will be fine with respect to visibility. If anyone said that rate is 'hard rain', they are wrong.
posted by SaltySalticid at 11:25 AM on August 8, 2022 [1 favorite]
If you're driving and begin to feel unsafe on the road due to conditions, put your hazard flashers on, move into the right lane, and slow down to a speed that feels more manageable. Keep driving slowly and steadily with your hazards on until you can safely pull off--either by taking an exit and driving somewhere you can park, or onto a designated highway pull off area. NOT the shoulder or side of the road, those are not safe places to stop at any time, but especially when visibility is reduced.
posted by phunniemee at 12:05 PM on August 8, 2022 [1 favorite]
posted by phunniemee at 12:05 PM on August 8, 2022 [1 favorite]
Response by poster: Phunniemee -- thank you for this. I agree with this. There are just times in this region where the rain is suddenly SO hard for about 15 minutes that literally no one can see the car ahead of them. You can't see an exit, you can't see anything absolutely at all. Then it turns back into normal heavy rain where you'd look for an exit or what have you. I have never been able to figure out how people deal with this, they just literally drive blind.
posted by ojocaliente at 12:57 PM on August 8, 2022 [1 favorite]
posted by ojocaliente at 12:57 PM on August 8, 2022 [1 favorite]
I don't think you'd be able to judge ahead of time. Rain changes. Usually as you need it not to rain, it'll start to pour.
I do think people literally just drive blind in those situations. If you stopped driving in the middle of the road, you'd get hit. If you can't see to find the side of the road to stop...?
posted by jenfullmoon at 1:19 PM on August 8, 2022
I do think people literally just drive blind in those situations. If you stopped driving in the middle of the road, you'd get hit. If you can't see to find the side of the road to stop...?
posted by jenfullmoon at 1:19 PM on August 8, 2022
I have never been able to figure out how people deal with this, they just literally drive blind.
My parents always pulled over to the shoulder and waited it out when this happened. I think a lot of people do that.
posted by showbiz_liz at 2:49 PM on August 8, 2022
My parents always pulled over to the shoulder and waited it out when this happened. I think a lot of people do that.
posted by showbiz_liz at 2:49 PM on August 8, 2022
I have never been able to figure out how people deal with this, they just literally drive blind.
I was on a family trip two decades ago, driving down I-10 through Louisiana, when Hurricane Claudette rolled in. Whole interstate full of traffic, on relatively narrow roads for a highway, nowhere to stop, and what I charitably would call 5% visibility. Every non idiot on the road that day pulled into the right, threw our hazards on, and drove sloooowly only each following the headlights in front of us. It was still extremely tense.
Occasionally we'd see someone zip by in the left lane (going maybe 40, a relative zip) but they were an extreme minority.
When things get very very bad on the road, you do what you need to do to drive safely, and set an example for others to follow. Most people do not want to die in a traffic accident. More than once in heavy rain I have been the first car on the road to throw my hazards on and people around me have followed suit.
If you CAN make a choice, try to get behind a big truck. They can see farther and are communicating with each other over coms and will know about obstacles before you do.
posted by phunniemee at 4:14 PM on August 8, 2022 [2 favorites]
I was on a family trip two decades ago, driving down I-10 through Louisiana, when Hurricane Claudette rolled in. Whole interstate full of traffic, on relatively narrow roads for a highway, nowhere to stop, and what I charitably would call 5% visibility. Every non idiot on the road that day pulled into the right, threw our hazards on, and drove sloooowly only each following the headlights in front of us. It was still extremely tense.
Occasionally we'd see someone zip by in the left lane (going maybe 40, a relative zip) but they were an extreme minority.
When things get very very bad on the road, you do what you need to do to drive safely, and set an example for others to follow. Most people do not want to die in a traffic accident. More than once in heavy rain I have been the first car on the road to throw my hazards on and people around me have followed suit.
If you CAN make a choice, try to get behind a big truck. They can see farther and are communicating with each other over coms and will know about obstacles before you do.
posted by phunniemee at 4:14 PM on August 8, 2022 [2 favorites]
Weather mapping just keeps getting better. I have something called Clime on my iPhone that has animated weather maps, I haven't comparison-shopped. Subscribe to weather alerts on your phone. Sometimes you can (not while actually driving, of course) see a nasty storm cell and be prepared or take a break.
posted by theora55 at 6:25 PM on August 8, 2022
posted by theora55 at 6:25 PM on August 8, 2022
Best answer: .03"/hr is just enough to give your wipers something to do, I'd think. The road might be slippery if you haven't had rain, but it shouldn't affect visibility. I haven't had a rain gauge handy when driving, but I'd imagine the conditions you're describing are at least .4-.5" hour, and maybe a good bit higher to really properly destroy visibility.
posted by wotsac at 9:39 PM on August 8, 2022
posted by wotsac at 9:39 PM on August 8, 2022
I use the DarkSky app (iPhone link) which gives hour by hour precipitation rate predictions (and I generally find to be quite accurate, though I haven’t paid much attention to precipitation rate per se). You could check it the morning of, and at rest stops, to see if there’s an hour you feel like you need to wait out.
posted by suviko at 10:04 PM on August 8, 2022
posted by suviko at 10:04 PM on August 8, 2022
Response by poster: Update: So, even .03 inches/hour can cause a huge dump of rain with severe visibility issues for about 15 minutes, then quickly dry up or become a light drizzle. (Though the answers about how to drive in the rain are great and should be very helpful to future askme readers as well, this question was specifically about how to interpret the numbers on weather apps to understand the likelihood of poor visilibity. And the answer is: you can't tell from the numbers. Even something that adds up to a drizzle over the course of an hour can cause super heavy rain over a short period, the kind where you can't even see the shoulder for a few minutes, or the hazards of the car in front of you. But then, if it's a low number, it ends soon.)
Thanks for all the answers!
posted by ojocaliente at 6:49 AM on August 10, 2022
Thanks for all the answers!
posted by ojocaliente at 6:49 AM on August 10, 2022
This thread is closed to new comments.
posted by ojocaliente at 11:07 AM on August 8, 2022