I really wish people would get off this 'can't evacuate the whole city of 6.5 million' idea. You don't need to evacuate all of Houston. Many of those 6.5 million people are not flooded. However, you can and should try to evacuate those in the most flood prone areas. It is difficult to 'shelter in place', when your place has water up to the eaves!

Forecasters were predicting extreme record breaking rainfall amounts for the Houston area well before Harvey made landfall. Many areas in an around Houston have repeatedly flooded in the past. With that weather prediction, it was literally a no brainer that those areas that flooded in the past would flood this time. There was absolutely no reason why the authorities couldn't have tried to get people to evacuate the well known flood prone areas. However, as I noted up-thread, that takes planning, which apparently wasn't done. If even half of the people in known flood prone areas had evacuated (which would be way less than the 6.5 million number I keep hearing) it would have freed up rescue resources to concentrate on those areas which no one anticipated would flood.

Full disclosure: I'm more than a little familiar with the issues in Houston. I spent my career as a geo in the oil patch, with the bulk of that time in Alaska. However, I worked in Houston for several years, and lived west of town in Katy. Even while living in Alaska, I've also traveled down there on business on many occasions. My wife and I have ridden our mountain bikes on the levee around Barker Reservoir, the one that they are now releasing water from out of fear the dam might fail. I was there in 2001 and saw the flooding from Tropical Storm Allison.

I am not familiar with the area and only posted what was in the news link. I imagine though, even if they had decided to evac 500,000 to a million people, it would have been a massive undertaking.

“Where do you take them? How do you get them where you want them to go?” Paulison said. “Who’s going to take care of them when they get there?” -from the article posted above.

Sage comments. It's like the whole "bug out" concept, which, while terribly "in" right now, is a horribly flawed idea.

A major metropolitan area has tons of resources - food, water, medical care, shelter, transportation and manpower. If you "bug out" voluntarily - leaving the city behind to flee into the wilderness, once you have exhausted the resources of your nifty "bug out bag", where do you get more stuff? How will you survive out of your element? Where do you find shelter? How do you connect with people who are willing to help you and avoid people who are willing to do you harm?

It's a three to four hour drive (without traffic delays) to Dallas, San Antonio, and Austin - the nearest cities of any decent size. Even using contraflow evacuation lanes (southbound interstate lanes converted to nothbound travel) which they created after the Rita evacuation fiasco, you basically only have 4 main lanes of traffic to Dallas/Ft. Worth, four to San Antonio, and four to Austin.

With strategically pre-positioned fuel tankers, water supplies, and deployed emergency personnel along these routes (something else they have implemented), you will have massive traffic jams for 150-200+ miles in every direction which may have flooded in places trapping thousands upon thousands of people out in the open with nowhere to go.

And staged evacuations do not work. The hurricane evacuation plans in place call for the folks living directly in the Coastal Zone to evacuate first, then folks further inland in Zone A next and so on. Storm surge affected areas, basically. Maybe 1 to 1.5 million people. During the Rita evacuation, people who had ZERO danger of being affected by storm surge overreacted and decided to evacuate. They estimated that 3.7 million people tried to leave. All at once. You can't control that.

You can't control irrational people with poor critical decision-making skills who aren't able to understand that those poor people in New Orleans up on their rooftops waving at helicopters lived in areas below sea level surrounded by levees that failed. Half the people in my subdivision (140' above sea level - 70 miles away from the coast) evacuated before Rita. Right now, we are still flood-free.

I want to close on a positive note. People are helping people here in the Houston area. It's what we do here in Texas. In addition to the government shelter efforts, churches and other non-governmental groups are taking in displaced people and citizens are volunteering their time and donating supplies to help those in need. The outpouring of help has been so overwhelming, that some shelters have turned away volunteers and donations. This will be a long term recovery for many people however, so please consider donating a contribution to the American Red Cross.

You are herding cats when directing a large scale evacuation. Even in mandatory evacuation situations, there are folks who will not leave - they don't believe the forecasts, this has never happened before, the gov'mnt is lying, I don't want to go to a 'FEMA" camp, etc. Personal factors play a large role in deciding whether or not to move.

That area of Texas is relatively flat, low lying coastal plain, and it not immediately obvious which localities will flood (although careful mapping should help with this problem). The typical hurricane hits the coast, loses strength, and moves - typically to the north and east, and the rainfall is dispersed over a very wide area, often with beneficial results. In this case, weather patterns confined Harvey to the Texas coast, and precip is concentrated.

My sister is living (still) in Houston. Talking to her before the event, she was fairly complacent and had no desire to leave. She lives on fairly high ground and has a secend story, so did OK in the event.

Still, one wonders why development is allowed within a 100 year flood plain, anywhere. For that matter, when i become Emperor of the Universe, one of my first executive orders will be to evacuate New Orleans and turn it into the world's largest National Alligator Preserve.

Standing down from soap box...

ONE thing that would really help - is just to know which roads are passable. Not just for Houston, but many other towns in Texas. There are lots of TX residents saying (in the news) ... "we were going to evacuate, but we were not sure if we could get through in our car. It's not a good idea to get stuck in flood waters in your car, so we decided to shelter in our house". That story has been quite common.

People need news - with fast updates - about local road conditions. That type of really helpful data has not been available.

The only people who needed to evacuate were those in likely flood zones. Evacuation of the entire city of Houston is not realistic, but specific areas could have been evacuated.

I live in SOCAL and for wildfires you only evacuate areas under direct threat -- wind conditions and fuel. In the case of Houston, it was known that Harvey would be a major rain event. City officials should have known which parts of Houston were prone to flooding and acted accordingly. They told everyone to shelter in place.

This is why people learn to disregard city officials. They totally blew it and now they are trying to justify their decision with talks of how it's impossible to evacuate the entire city.

Not sure why people would bug out in the wilderness. If you are going to bug out, go quickly before everybody else does and have money ready. Book your vacation, while traveling to a save distance. Why get stuck in a region where everybody else is running too. I would rather play as a tourist somewhere way further, than a refugee.

If you decide to leave, leave early. Otherwise, your options are limited or eliminated.

You raise a good point. Such mapping seems a basic necessity to any sort of emergency planning, especially flood evacuation planning. With such maps, and a reasonable estimate of how high the water will get, it should be possible to ID the most flood prone areas and evacuate them to local, higher grounds, instead of trying to evacuate masses of people hundreds of miles.

Where I live, there are detailed maps (by the Feds) of the 100 year flood plane. I think they exist for most of the country on-line. They certainly would be a good place to start the planning.

That kind of mapping already exists. One of the links I posted earlier ( Boomtown, Flood Town ) shows the 100 Year and 500 Year Flood Plain on a regional scale. Also note the dots showing buildings that have historically flooded that are outside of those flood plains. With GIS it would be easy to incorporate that into the flood plain maps. The USGS supplies free DEM data ("Digital Elevation Model") at a 10 meter map grid for the entire lower 48 states. While this was originally derived from 7.5 minute topo maps, it is continually being updated as better data ( LIDAR for example) becomes available. I know that NOAA has also been doing high precision DEM mapping for Texas coastal areas.

So tell me Blacktop, do you think a staged evacuation would have been worse than what is happening now? Would it be worse to be stuck in a massive traffic jam on higher ground North of Houston, rather than being stuck on a rooftop in the rain? Right now we are seeing a massive extremely chaotic evacuation using boats, helicopters, air mattresses, kayaks, etc.

Yes, there will be an element of chaos in any large scale evacuation. However, experience from wildfire areas shows that it is possible to do. Realistic advanced planning helps a lot. Remember the "7P" principle. Much better to get at least some of the most threatened people out ahead of the flooding, than to mount a massive ad hoc rescue effort after the water rises and the roads are blocked.