The Foehn effect: why it's warmer on one side of a mountain than the other
Anywhere that has mountains will experience the Foehn effect, and the higher the mountains the greater the warming. In the Alps and North America, where mountain ranges are covered in glaciers and snow, this sudden rise in temperature can trigger avalanches, especially in the spring. The Foehn effect's advantage, where there is a fairly consistent prevailing wind, is that farmers get an earlier and longer growing season on the lee side of the mountain range. The simple rule is that whichever way the wind is blowing from, it is going to be warmer on the other side of the hill.
As the climate crisis bites, an unfortunate consequence of the Foehn effect is bigger wildfires. Mountain dwellers are being warned that as warm dry air sweeps down the side of a mountain it will fan the flames, making a dangerous situation worse.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Telegraph
2 hours ago
- Telegraph
Do not open doors unnecessarily during Storm Floris, Met Office warns
The Met Office has warned people to only open doors where 'needed' during Storm Floris. The forecaster said the storm will bring 'unusually windy weather' for this time of year, with 85mph gales and heavy rain set to hit parts of the UK. A yellow warning for wind has been issued for northern parts of the country from 6am on Monday to 6am on Tuesday. In a post on X linking to advice on how to stay safe in a storm, the Met Office said: 'Storm Floris is forecast to bring strong winds and heavy rain for parts of the UK from Monday. 'Stay #WeatherReady and check out some advice from our partners about keeping yourself, your home, and your garden safe.' #StormFloris is forecast to bring strong winds and heavy rain for parts of the UK from Monday Stay #WeatherReady and check out some advice from our partners about keeping yourself, your home and your garden safe — Met Office (@metoffice) August 2, 2025 Other advice includes 'open[ing] internal doors only as needed, and close them behind you', parking vehicles in a garage, secure loose objects such as ladders, garden furniture or anything else that could be blown into windows and stay indoors as much as possible. Forecasters add that if you need to leave your home, then try not to walk or shelter close to buildings and trees. The Met Office said the strongest winds will most likely affect Scotland on Monday afternoon and night, but 'there remains some uncertainty in the depth and track of Floris'. It added: 'Winds will first ease in the west during later Monday but remaining very strong overnight until early Tuesday in the east. Heavy rain may also contribute to the disruption in places.' The warning zone covers Scotland, parts of Northern Ireland, north Wales and the north of England. Alex Burkill, a Met Office meteorologist, said: 'It's not that often that we get storms during the summer months, but it's worth bearing in mind that at this time of year we could see some increased disruption because of the fact that the trees are full of leaf and there are lots of outdoor activities planned. 'You may be camping, you may be trying to head to a festival... as a result, we could see some significant impacts because of not only the rain, but also the winds.' The Met Office added that flying debris may cause injuries and pose a danger to life in places inside the warning zone, along with large waves and beach material being thrown onto sea fronts, coastal roads, and properties. Forecasters also said it was possible that tiles will be blown from roofs, and there may be power cuts, while rail, air, and ferry services could be disrupted. Storm Floris is the sixth named storm of the 2024-25 naming season, which runs from early September to late August, and January's Storm Eowyn was the most recent. Named storms are more frequent in late autumn and winter but are 'not uncommon' for summer, the Met Office said. The weekend will see a combination of sunshine and showers before Floris hits. Meanwhile, the Environment Agency said the forecast rain will not counteract the impacts of the driest start of the year since 1976 but will provide some short-term relief. The UK has experienced three heatwaves so far this summer, which have left four regions of England in drought. Stuart Sampson, the Environment Agency national drought manager, said that river flows and reservoir levels continue to be a concern, adding: 'Everyone can play their part by using a little less water to ease pressures on our water supply.'
The Independent
11 hours ago
- The Independent
Storm Floris map shows where heavy rain and up to 85mph winds are set to hit the UK
The UK is bracing for Storm Floris to hit on Monday, with northern Eangland and Scotland set to be hit the hardest, with possible winds of up to 85mph. The Met Office has issued a Yellow wind warning over winds, which covers Northern Ireland, north Wales, northern England, and the whole of Scotland, where the hardest winds are expected along the coasts. The warning will be i n force from 6am on Monday until 6am on Tuesday. Heavy rain is also expected, with transport disruption possible. Matthew Lehnert is a Met Office Chief Meteorologist. He said: 'Across the warning area, many inland areas are likely to see gusts of 40-50mph, with 60-70mph more likely at higher elevations and around exposed coasts in Scotland. There is a small chance that some locations here could even record gusts of 85mph.' Going into Tuesday, the Yellow warning will remain with the east of the warning area still expected to see strong winds; however, the gusts will first begin to ease to the west on late Monday. Flying debris may cause injuries and pose a danger to life in places inside the warning zone, the Met Office said. As could 'large waves and beach material being thrown on to sea fronts, coastal roads and properties', it added. It is possible tiles will be blown from roofs and there may be power cuts. The weather could also disrupt road, rail, air and ferry services, and close bridges. Storm Floris is the sixth storm to be named in the 2024 to 2025 season. The last named storm was Éowyn in January. The Met Office said that while it is more likely that named storms hit in late autumn and winter, they can happen in summer. It follows the driest spring in the UK for more than a century, as well as three heatwaves in quick succession. June was the warmest month since records began. The hot temperatures left swathes of the UK on hosepipe bans as farmers warned of potential food shortages after being forced to harvest their crops early to avoid damage. Last month was the UK's fifth warmest July on record, according to provisional figures from the Met Office. The mean average temperature across the month was 16.8C, ranking it behind 2006 (17.8C), 2018 (17.2C), 1983 (17.1C) and 2013 (17.0C). All four UK nations recorded one of their top 10 warmest Julys: Scotland and Northern Ireland saw their sixth warmest, England its seventh and Wales its tenth. Met Office temperature records begin in 1884. But July also brought increasingly wet and temperamental weather. On Thursday, parts of England were warned about the possibility of flash floods in the Midlands, South and East of England and London. Heavy rain proceeded to pummel parts of the south of England. Less than a week earlier, parts of the UK were enjoying highs of 28C. The weather should stay relatively dry over this weekend ahead of the storm. The latest Met Office update says there will only be 'small amounts of cloud'.
Reuters
a day ago
- Reuters
Explainer: How prepared are U.S. grid operators for extreme heat this summer?
Aug 1 (Reuters) - Grid operators across the U.S. are revamping their forecasting methods, introducing reforms to power markets and streamlining interconnection processes to quickly connect more energy to the grid, as a potent combination of extreme weather and data center growth elevate power demand this summer. High temperatures and the expansion of power-hungry data centers are set to push 2025 summer power consumption to higher levels than the past four summers, federal regulators said earlier this year. Heat waves have already strained the power grid in parts of the country in recent weeks. 'Extreme weather events are becoming more common, and we are adjusting our planning for that,' said Dan Lockwood, PJM Interconnection spokesperson. Here's how grid operators are positioned to meet demand this summer, and longer-term measures they are taking to shore up the system. Heading into the summer, PJM had forecast power consumption to peak at just over 154,000 MW. The company, which is the largest grid operator in the U.S. and serves one in five Americans, said it is prepared to meet that demand, but warned that it could touch an all-time high of 166,000 MW in an extreme scenario. In that case, it would call on customers to reduce their power use in exchange for compensation. PJM has been streamlining its interconnection process to bring new power onto the grid. It has also fast-tracked projects that do not require extensive grid upgrades to connect to the system to get them online quicker. California Independent System Operator estimated it has a power surplus of 1,451 MW this summer, measured against the industry-standard, one in 10 year emergency event. That marks a reversal from three years ago, when it estimated a shortfall of 1,700 MW. CAISO has also been moving to quickly add new power to its grid, with around 25 GW added over the last five years, said Dede Subakti, vice president of system operations. Much of this has been battery storage, which helps balance supply and demand, bringing CAISO's total pool of battery storage to 11 GW. 'With all this additional capacity, we're sitting pretty good with 2025 summer,' Subakti said. However, the grid could still see shortfalls if a prolonged heat-wave affects the entire West, or if potential wildfires damage power transmission lines, CAISO said. ISO New England anticipates electricity demand will touch 24,803 MW this summer under normal weather conditions - and potentially 25,886 MW in case of extended heat waves - but expects to have adequate power to meet that. ISO-NE is one of the grid operators that is evaluating changes to its capacity auction to bolster grid reliability. This includes transitioning to a 'prompt' auction, held shortly before the power is needed, compared with the current practice of holding them three years in advance. In addition, it is looking to move to two seasonal commitment periods per year for the auction, to tackle the distinct risks that summer and winter demand pose to the grid. It intends to file an initial proposal for this new market structure with federal regulators before year end. Midcontinent Independent System Operator predicted that peak demand in its footprint could reach nearly 123 GW this summer, with roughly 138 GW of available power generation to meet that. Like other grid operators, however, it warned that extreme weather events still present a risk to the grid. MISO, which has been operating near its minimum reserve margin requirement since 2022, has also been making changes to its wholesale markets as grid risks grow, including assessing the reliability of its infrastructure on a seasonal basis. It implemented a 'reliability-based demand curve' in its latest auction, under which the price of electricity resources increases as the grid approaches its minimum requirements. MISO has added around 31 GW of nameplate power to its grid from 2020 through mid-2025, with another 10.9 GW estimated for this year. Meanwhile, nearly 11 GW of power resources have or are set to retire between 2020 through early 2026.
