Why rain on snow in the California mountains worries scientists

Rain-on-snow events have resulted in some of the nation’s most destructive and costly floods

Keith Musselman

Down To Earth | March 15, 2023

Another round of powerful atmospheric rivers is hitting California, following storms in January and February 2023 that dumped record amounts of snow. This time, the storms are warmer, and they are triggering flood warnings as they bring rain higher into the mountains – on top of the snowpack.

Professor Keith Musselman, who studies water and climate change at the University of Colorado’s Institute of Arctic and Alpine Research, explained the complex risks rain on snow creates and how they might change in a warming climate.

What happens when rain falls on snowpack?

For much of the United States, storms with heavy rainfall can coincide with seasonal snow cover. When that happens, the resulting runoff of water can be much greater than what is produced from rain or snowmelt alone. The combination has resulted in some of the nation’s most destructive and costly floods, including the 1996 Midwest floods and the 2017 flood that damaged California’s Oroville Dam.

Contrary to common belief, rainfall itself has limited energy to melt snow. Rather, it is the warm temperatures, strong winds and high humidity, which can transport substantial energy in the form of latent and sensible heat, that predominantly drive snowmelt during rain-on-snow events.

CO2 Levels Are the Highest in a Million Years as Extreme Weather and Flooding Rage Across the Globe

Juan Cole

Countercurrents | September 01, 2022

Girls use a temporary raft across a flooded street in a residential area after heavy monsoon rains in Karachi on July 26, 2022. A weather emergency was declared in Karachi as heavier-than-usual monsoon rains continue to lash Pakistan’s biggest city, flooding homes and making streets impassable. (Photo: Rizwan Tabassum/AFP via Getty Images)

CNN reports that satellite photos show that the overflowing Indus has created a new body of water in southern Pakistan some 62 miles (100km) wide. It will take days or weeks for the water to recede, and in the meantime millions are left homeless and over all, 33 million people have been affected by the worst monsoon floods in recorded history. CNN quotes Pakistan’s Climate Minister Sherry Rahman as saying “That parts of the country ‘resemble a small ocean,’ and that ‘by the time this is over, we could well have one-quarter or one-third of Pakistan under water.’”

Because of our burning of fossil fuels to drive cars and heat and cool buildings, the world is heating up. But the Indian Ocean is heating up a third faster than the rest of the world. Very warm waters in the Bay of Bengal are helping create more destructive cyclones and flooding. The air over warming waters contains more moisture than the 20th century average. Warming waters also make the winds that blow over them more erratic, and wayward winds from the Arabian Sea helped push the heavy monsoon rains farther north than they usually extend.

Extreme weather events in India made women, children more vulnerable to modern slavery, flags report

Kiran Pandey

Down To Earth | September 21, 2021

Climate change-induced extreme weather events put women, children and minorities at risk of modern slavery and human trafficking. The phenomenon is on the rise in India, among other countries, warned the International Institute for Environment and Development (IIED) and Anti-Slavery International in a recent report. 

Modern slavery — including debt bondage, bonded labour, early / forced marriage and human trafficking — converge with climate change, particularly climate shocks and climate-related forced displacement and migration, the report said.

Freak US winters linked to Arctic warming

Models suggest that distortions in polar-vortex winds can send chilly air hurtling southwards. But some climate scientists remain unconvinced.

Quirin Schiermeier

Nature | September 03, 2021

Unusually severe winter storms brought snow to Austin, Texas, in February. Credit: Montinique Monroe/Getty

Recent spells of unusually cold winter weather in the United States and other parts of the Northern Hemisphere could be a paradoxical consequence of the climate warming in the Arctic, according to a study based on decades of atmospheric observations. However, it is still unclear whether this represents a long-term trend that will persist as the world heats up.

The Arctic’s rate of warming is twice that for Earth as a whole, and some climate researchers have long suspected that this rapid Arctic warming can trigger anomalies in the winds around the North Pole, with consequences for weather thousands of kilometres farther south.

Cyclone Yaas is Another Reminder of The Urgent Need for Coming Together to Face Difficult Times

ENVIRONMENT 

Bharat Dogra

Countercurrents | May 27, 2021

One cyclone coming soon after another and that too in pandemic times need not and should not lead to a sense of helplessness. The country has  the capacity to overcome bigger challenges, and this has been revealed several times in the middle of great difficulties. In a more specific context,  frontline coastal states like Odisha and West Bengal have shown significant improvements in cyclone related preparations and rescue efforts. At the  level of its wide coastal region, the nation has improved the warning systems.

However we cannot afford to rest on our laurels. As there are definite and proven signs that  the threat from disasters in general and cyclones in particular in times of climate change is increasing, we need to improve our disaster-preparedness much more.

LIFE: Post-snow storm: Over a million Texans are still without drinking water

WEATHER CRISIS IN U.S.

A Journal of People report

Over a million Texans are still without drinking water. Smaller communities and apartments are facing the biggest challenges, said reports. And oil refineries, chemical plants and other industrial operators emitted 3.5 million pounds of excess pollution during the winter storm and power crisis in Texas, according to an analysis of company notices provided to state regulators. The recent snowstorm created havoc in the life of the people in Texas. Mainstream media reports have documented the life there in Texas.

A report by The Texas Tribune said:

“Over 1.4 million Texans still faced water disruptions on Wednesday afternoon, more than a week after Texas’ winter storms wreaked havoc on the state’s power grid and water services.

‘A humanitarian crisis’: Cold and snow put millions in danger in Texas: 38 dead

EXTREME WEATHER IN U.S. 

Countercurrents | February 19, 2021

Texas’s freeze entered a sixth day on Thursday. At least 31 people have died as of Wednesday afternoon as a result of the severe weather in Texas. But some media reports said, days of glacial weather have left at least 38 people dead in the U.S. The snow made many roads impassable, disrupted coronavirus vaccine distribution and blanketed nearly three-quarters of the continental U.S. And that number is expected to climb with no end to the Texas nightmare in sight.

Media reports from the U.S. said:

More than 3 million Texans were without power. But some media reports put the number to more than 4 millions. Some have gone four days without electricity after a rare winter storm slammed the U.S. state and created bitterly cold and unlivable conditions. All of the water pipes in many homes are frozen.

Increased Sea Surface Temperature Affecting Indian Monsoon: Study

INDIAN WEATHER AND GLOBAL WARMING

India Science Wire | October 07, 2020

The climate across the world is changing in many ways, triggered by different global warming phenomena that have resulted in a change in the monsoon onset time and pattern. The process is affecting the agricultural yield. Any excess or little rainfall is, therefore, detrimental to these crops.

A new study on variability in the Mascarene High (MH) during global warming hiatus (GWH) revealed that the region experienced significantly increased sea surface temperature (SST) during this period (1998-2016).

The Mascarene High (MH) is a semi-permanent subtropical high-pressure zone in the South Indian Ocean. Apart from its large influence on African and Australian weather patterns, it also helps in driving the inter-hemispheric circulation between the Indian Ocean in the south and subcontinental landmass in the north.

Expect a Wet September, Late Monsoon Withdrawal Due to La Niña

WEATHER IN NORTH PACIFIC OCEAN

Akshit Sangomla

Down To Earth | August 14, 2020

There is a 50-55 per cent chance for the development of a La Niña condition in the equatorial Pacific Ocean during the autumn of 2020, according to the latest update by the United States National Oceanic and Atmospheric Administration.

There is a 50 per cent chance that it might continue into the winter season as well. Currently, El Niño Southern Oscillation (ENSO) neutral conditions are prevailing in the equatorial Pacific Ocean.

During the last four weeks, equatorial sea surface temperatures were below average from the International Date Line to the eastern Pacific and were above average in the western Pacific. The International Date Line is an imaginary line on the Earth’s surface, defining the boundary between one day and the next.

El Niño in retreat

Granma | 27 April, 2016

Photo: http://www.nature.com

After reaching its peak intensity between December and January, and featuring among the strongest three periods of the past 60 years, alongside those of 1997-1998 and 1982-1983, the current El Niño Southern Oscillation (ENSO) warm phase continued its gradual decline in March, as sea surface temperatures in the equatorial Pacific Ocean declined.