2015 was Texas' wettest year on record

Relentless rains and other storms made 2015 Texas' wettest year on record. Click through our photos of the floods, blizzard and tornadoes that wreaked Lone Star havoc this year. Relentless rains and other storms made 2015 Texas' wettest year on record. Click through our photos of the floods, blizzard and tornadoes that wreaked Lone Star havoc this year. Photo: Houston Chronicle Photo: Houston Chronicle Image 1 of / 335 Caption Close 2015 was Texas' wettest year on record 1 / 335 Back to Gallery

Texas saw ruinous hail storms, floods, tornadoes, blizzards and even an acute summer drought in 2015. Add it all up, and this past year was the state's wettest since record-keeping began in 1895, according to official numbers through November and federal estimates for December.

"I've called this year's climate 'Texas' wild ride," said state climatologist John Nielsen-Gammon. "We recovered from one drought, then had another one, then recovered from it. Texas had its wettest month ever, and its wettest storm ever, and the wettest storm was not in the wettest month."

Preliminary figures show weekend rains that accompanied a North Texas tornado outbreak dropped an average of 1.3 inches across the state. That brings the statewide yearly rainfall total to 41.39 inches, surpassing 40.22 inches in 1941 and 39.45 inches in 1919 for the top spot on the rankings. In Houston, yearly rainfall was 20 inches above average, which ranked fifth overall.

Experts credit phenomenal global-weather patterns in 2015 for the relentless storms, but also point to decades-old climate models, which long ago predicted that an earth warmed by greenhouse-gas emissions would see a higher volume of intense downpours like the ones that struck Texas this year.

"The intensity of storms is going up," said Ron Sass, fellow in global climate change at Rice University.

Such wet weather is expensive; in October, the Houston Chronicle reported that statewide flood damages were estimated at $3 billion, largely in repair costs to water-logged roads with soaked foundations. That figure didn't cover the recent tornado outbreak that destroyed hundreds of structures in North Texas.

RELATED: Texas flood damage could top $3 billion for 2015

Mark Hanna, a spokesman for the Insurance Council of Texas, said he expected billions of dollars in homeowner claims, but couldn't provide estimates for damages to vehicles or commercial property.

"It's just been storm after storm after storm," he said Tuesday from Dallas, where he'd traveled to assess tornado damage. "I couldn't keep up with it."

All the action has kept officials on their toes. Michael Walter, a spokesman for Houston's Office of Emergency Management, called this year the busiest he's seen. The office has taken some lessons to heart; Walter said it has kicked off a monthly weather training drill, stepped up communication efforts with weather forecasting agencies and pushed to register Houstonians to receive official emergency alerts on their cell phones.

"I think people are paying a bit more attention to these rain events now," he said.

Global patterns

The amount of rain that hits Texas in concentrated bursts has grown steadily over the last 40 years, according to Gerald North, a veteran climate researcher at Texas A&M University. That effect has long been predicted by computer models of greenhouse gas-induced climate change; warmer air currents hold more moisture, so when storm clouds break, there's more water to fall.

"It seems to be a real trend," he said. "Probably more of our rain will be concentrated in these heavy events."

But a global weather phenomenon this year, El Niño, also exacerbated Texas storms. About every three to 12 years, water on the surface of the Pacific Ocean gets so warm that it heats the air above it, which rises in massive columns, thwarting the typical flow of atmospheric currents. Typically, it bumps the subtropical jet stream north, directly into Texas airspace, bringing a steady supply of airborne moisture to Lone Star skies.

RELATED: Rainy weather likely to continue all year as El Niño builds strength

Texas "is particularly sensitive to the influence of this natural cycle," Neilsen-Gammon said. This year saw the strongest El Niño on record by many metrics.

First rains were unexpected

At the start of 2015, Texas' searing four-year drought lingered, but finally faded with rains in early May. Then tremendous downpours over Memorial Day weekend swept across Central and Southeast Texas, washing homes from foundations, causing tens of millions of dollars in damage, and shutting down wide swaths of Houston. The storms left more than 30 people dead in Texas and Oklahoma

"Before the flood, the forecasts were just really off," Walter said. "We got in a situation where rain was falling much faster than anticipated, and we ended up having to step up our response from zero."

RELATED: Rain was in the forecast, but not 162 billion gallons of it

Rescue boats plucked hundreds of Houstonians from swamped neighborhoods, up to 10,000 cars broke down in flooded roadways and citywide damage was estimated at almost $50 million. May became Texas' wettest month on record.

But it wasn't just the volume of rain that caused the disastrous Houston flooding, said Michael Talbott, executive director of the Harris County Flood Control District, which maintains 2500 miles of natural and man-made drainage channels around Houston. It was the concentration and intensity of downpours.

"We could have gotten through this year without any flooding had the rain been spread out a little more," he said.



Elsewhere in Texas, spring storms caused hundred of millions of dollars in damage to cars and homes, particularly in a late-April outbreak of server hail and tornadoes, said Hanna.

But rains that were a nightmare in urban areas were welcome relief for farmers and ranchers, who had struggled since 2011 and through a record drought. Nature was heavy-handed with its compensation.

Cities flood and farmers struggle

"This year looked like it had a lot of promise," said Travis Miller, director of state operations for Texas A&M AgriLife Extensions Service, which monitors statewide agriculture. "Until the rain just wouldn't quit."

RELATED: Texas cattle sees first rebound from drought

Texas' most fertile fields lie in creek floodplains, where water delivers nutritious silt. But by late spring, too much water had left fields submerged.

When fields turn muddy, farmers can't take their tractors out. Many in the plains couldn't plant their cotton—Texas' highest-grossing crop—until the last day of the planting season in June. Then the rain stopped. By September, half of the state—though not Houston—was in drought again, and the rains didn't return until it was too late for good cotton.

Then. between Oct. 22 and Oct. 25, the wettest single storm in Texas history struck, Nielson-Gammon said. One Central Texas rain station logged 0.15 inches of rainfall between June and September, and another reported 0.15 inches per minute on Oct. 30. Streets and neighborhoods flooded from Houston to Austin to Dallas.

Wheat planting was then delayed for muddy fields, and the rains didn't let up. Two thirds of the state's wheat crop never made it into the ground, Miller said.

"Overall, disappointing year," he said.

Andy Vestal, director of emergency management for AgriLife, declined to comment for this article, saying he was busy with state and local emergency response since weekend storms in North Texas.

A changing climate

The dramatic weather bears the markers of man-made climate change, according to Andrew Dessler, a professor of atmospheric sciences at Texas A&M University and former senior tech policy analyst at the White House.

Decades of computer models with millions of data points and variables have suggested that precipitation would concentrate into heavy outbreaks as the climate warms. This year is strongly poised to overtake 2014 as the Earth's warmest year on record, according to federal data.

"There's more energy in the atmosphere because of the higher temperature," said Sass at Rice. "So weather in general is becoming more intense."

Sass started studying climate change in 1988, he said, when most of its outcomes were very theoretical. But starting in the late 1990s, he said, the climate started producing precisely what the earlier models had predicted, motivated by a steady warming trend.

RELATED: Study: Climate change could ravage Texas - 10 key outtakes

Scientists credit that trend to centuries of burning fossil fuel. Since the start of the Industrial Age, more than 350 billion tons of carbon has wafted out of smokestacks and exhaust pipes into Earth's air, in the form of methane or carbon dioxide. Those molecules—named greenhouse gasses for these heat-reflecting properties—bear a characteristic structure that reflects space-bound radiation back to the planet's surface, causing it to warm.

Scientists acknowledge they can't pin down precise manifestations of climate change, thanks mostly to the complexity of Earth systems. But so far, events have lined up well with predictions made decades ago via climate change models.

"I would not at all be surprised if at some point in the future we look back on this and we find out it was all driven by climate change," Dessler said. "But as of right now we're not really able to prove that."

In the coming months, heavy rains are unlikely to taper off. El Niño typically peaks between December and January, and should continue bolstering Texas storms through May, as the phenomenon's influence on the jet stream wanes, Nielsen-Gammon said.

An El Niño as strong as this year's is typically—but not always—followed by its counterpart, La Niña, which moves atmospheric moisture streams away from Texas, heightening the chance for drought.