A Record of Change—Science and Elder Observations on the Navajo Nation is a 25-minute documentary about collaborative studies using conventional physical sciences, combined with tribal elder observations to show that local knowledge and conventional science partnerships can effectively document ecosystem change and determine the resulting challenges to livelihoods.&
When does a drought begin and end?
The beginning of a drought is difficult to determine. Several weeks, months, or even years might pass before people know that a drought is occurring. The end of a drought can occur as gradually as it began.
The first evidence of drought is usually seen in records of rainfall. Within a short period of time, the amount of moisture in soils can begin to decrease. The effects of a drought on flow in streams and reservoirs may not be noticed for several weeks or months. Water levels in wells might not reflect a shortage of rainfall for a year or more after a drought begins.
Soaking rains are the best medicine to alleviate drought. Water that enters the soil recharges groundwater, which in turn sustains vegetation and feeds streams during periods when it is not raining. A single soaking rain will provide lasting relief from drought conditions, but multiple such rains over several months may be required to break a drought and return conditions to within the normal range. Even when a drought has been broken it may not be truly over. The benefits of substantial rainfall such as from a tropical storm may last for months, but a return to normal rainfall patterns and amounts is necessary for conditions in streams, reservoirs, and ground water to also return to normal.
Learn more:
Related
What causes drought?
Where in the Nation are droughts or very low flows occurring now? How can I see these sites on a map and get to the data?
Why doesn't a drought end when it rains?
What are the long-term effects of climate change?
How can climate change affect natural disasters?
What is the difference between global warming and climate change?
What are some of the signs of climate change?

A Record of Change—Science and Elder Observations on the Navajo Nation is a 25-minute documentary about collaborative studies using conventional physical sciences, combined with tribal elder observations to show that local knowledge and conventional science partnerships can effectively document ecosystem change and determine the resulting challenges to livelihoods.&
This short video is one of a series of four total shorts highlighting USGS water science in California's Delta region. The Sacramento-San Joaquin Delta is the hub of the state's water system. Water quality touches on all aspects of life. Teams of U.S.
This short video is one of a series of four total shorts highlighting USGS water science in California's Delta region. The Sacramento-San Joaquin Delta is the hub of the state's water system. Water quality touches on all aspects of life. Teams of U.S.
The surface level of Lake Mead in Nevada and Arizona has fallen to a historic low as 16 years of ongoing drought in the American Southwest continue to impact the Colorado River Basin.
The surface level of Lake Mead in Nevada and Arizona has fallen to a historic low as 16 years of ongoing drought in the American Southwest continue to impact the Colorado River Basin.

A scientist from the University of California, Berkeley climbs a giant sequoia to measure its drought stress.
A scientist from the University of California, Berkeley climbs a giant sequoia to measure its drought stress.
A hydrologic technician from the USGS Idaho Water Science Center measures streamflow in Homer Creek near Herman, ID. The USGS is collecting data at hundreds of sites on rivers and streams in six western states to document the 2015 drought. USGS scientists will analyze the data to identify which rivers and streams may be most vulnerable to future droughts.
A hydrologic technician from the USGS Idaho Water Science Center measures streamflow in Homer Creek near Herman, ID. The USGS is collecting data at hundreds of sites on rivers and streams in six western states to document the 2015 drought. USGS scientists will analyze the data to identify which rivers and streams may be most vulnerable to future droughts.
Drought conditions at Canton Lake, Oklahoma.
Drought conditions at Canton Lake, Oklahoma.
Stillwater Creek in drought conditions
Stillwater Creek in drought conditions

Radium Springs, Georgia, during drought conditions.
Radium Springs, Georgia, during drought conditions.
The white colored rock (approximately 100ft high) shows the drop in the water level of Lake Mead as a result of the ongoing 10-year drought along the Colorado River.
The white colored rock (approximately 100ft high) shows the drop in the water level of Lake Mead as a result of the ongoing 10-year drought along the Colorado River.
The Vegetation Drought Response Index (VegDRI) incorporates satellite observations of vegetation to monitor at a finer spatial detail than other commonly used drought indicators.
The Vegetation Drought Response Index (VegDRI) incorporates satellite observations of vegetation to monitor at a finer spatial detail than other commonly used drought indicators.
Dead molluscs and raccoon tracks are concentrated in cracks in mud in the substrate of a dried-down tidal pond. Increased frequency and duration of droughts are predicted by some climate models.
Dead molluscs and raccoon tracks are concentrated in cracks in mud in the substrate of a dried-down tidal pond. Increased frequency and duration of droughts are predicted by some climate models.
California's hotter drought has already killed millions of trees, particularly in low-elevation forests.
California's hotter drought has already killed millions of trees, particularly in low-elevation forests.
2022 drought in New England
USGS integrated drought science
The role of snowpack, rainfall, and reservoirs in buffering California against drought effects
Flood- and drought-related natural hazards activities of the U.S. Geological Survey in New England
U.S. Geological Survey Climate and Land Use Change Science Strategy—A Framework for Understanding and Responding to Global Change
Drought Monitoring with VegDRI
Climate change and wildlife health: direct and indirect effects
Water availability for the Western United States--Key scientific challenges
Related
What causes drought?
Where in the Nation are droughts or very low flows occurring now? How can I see these sites on a map and get to the data?
Why doesn't a drought end when it rains?
What are the long-term effects of climate change?
How can climate change affect natural disasters?
What is the difference between global warming and climate change?
What are some of the signs of climate change?

A Record of Change—Science and Elder Observations on the Navajo Nation is a 25-minute documentary about collaborative studies using conventional physical sciences, combined with tribal elder observations to show that local knowledge and conventional science partnerships can effectively document ecosystem change and determine the resulting challenges to livelihoods.&
A Record of Change—Science and Elder Observations on the Navajo Nation is a 25-minute documentary about collaborative studies using conventional physical sciences, combined with tribal elder observations to show that local knowledge and conventional science partnerships can effectively document ecosystem change and determine the resulting challenges to livelihoods.&
This short video is one of a series of four total shorts highlighting USGS water science in California's Delta region. The Sacramento-San Joaquin Delta is the hub of the state's water system. Water quality touches on all aspects of life. Teams of U.S.
This short video is one of a series of four total shorts highlighting USGS water science in California's Delta region. The Sacramento-San Joaquin Delta is the hub of the state's water system. Water quality touches on all aspects of life. Teams of U.S.
The surface level of Lake Mead in Nevada and Arizona has fallen to a historic low as 16 years of ongoing drought in the American Southwest continue to impact the Colorado River Basin.
The surface level of Lake Mead in Nevada and Arizona has fallen to a historic low as 16 years of ongoing drought in the American Southwest continue to impact the Colorado River Basin.

A scientist from the University of California, Berkeley climbs a giant sequoia to measure its drought stress.
A scientist from the University of California, Berkeley climbs a giant sequoia to measure its drought stress.
A hydrologic technician from the USGS Idaho Water Science Center measures streamflow in Homer Creek near Herman, ID. The USGS is collecting data at hundreds of sites on rivers and streams in six western states to document the 2015 drought. USGS scientists will analyze the data to identify which rivers and streams may be most vulnerable to future droughts.
A hydrologic technician from the USGS Idaho Water Science Center measures streamflow in Homer Creek near Herman, ID. The USGS is collecting data at hundreds of sites on rivers and streams in six western states to document the 2015 drought. USGS scientists will analyze the data to identify which rivers and streams may be most vulnerable to future droughts.
Drought conditions at Canton Lake, Oklahoma.
Drought conditions at Canton Lake, Oklahoma.
Stillwater Creek in drought conditions
Stillwater Creek in drought conditions

Radium Springs, Georgia, during drought conditions.
Radium Springs, Georgia, during drought conditions.
The white colored rock (approximately 100ft high) shows the drop in the water level of Lake Mead as a result of the ongoing 10-year drought along the Colorado River.
The white colored rock (approximately 100ft high) shows the drop in the water level of Lake Mead as a result of the ongoing 10-year drought along the Colorado River.
The Vegetation Drought Response Index (VegDRI) incorporates satellite observations of vegetation to monitor at a finer spatial detail than other commonly used drought indicators.
The Vegetation Drought Response Index (VegDRI) incorporates satellite observations of vegetation to monitor at a finer spatial detail than other commonly used drought indicators.
Dead molluscs and raccoon tracks are concentrated in cracks in mud in the substrate of a dried-down tidal pond. Increased frequency and duration of droughts are predicted by some climate models.
Dead molluscs and raccoon tracks are concentrated in cracks in mud in the substrate of a dried-down tidal pond. Increased frequency and duration of droughts are predicted by some climate models.
California's hotter drought has already killed millions of trees, particularly in low-elevation forests.
California's hotter drought has already killed millions of trees, particularly in low-elevation forests.