Though meteorology has been around since the days of Aristotle (who coined the term), much of what we now know about weather systems has only been revealed with the advent of modern equipment such as radar and satellites. Yet, we find numerous statements regarding weather predictions and conditions in words of Hazal written some 2,000 years ago – many of which can be understood only now, as meteorologistscontinue to uncover secrets of Creation.
The Gemara (Taanit 2a) states that there are three phenomena which do not follow any laws that Hashem set into nature, but are contingent entirely upon His direct intervention: death, childbirth, and rainfall. As these three phenomena are not subject to specific laws of nature, it stands to reason that they cannot be predicted. Modern science has borne out what this Gemara teaches. In general, natural events occur based on a set of fixed, unchanging rules, and therefore in most scientific disciplines, scientists can predict the results of almost any process with certainty and accuracy. For instance, a physicist testing a physical system can predict the results of his efforts as long as he takes into account the various forces that are at play in the system. An exception to this rule is weather prediction. Weather prediction is so complex and involves so many factors, that even the most proficient meteorologists are unable to predict the weather even for the immediate future with perfect precision. And they are certainly unable to provide an accurate long-range weather forecast.
Why is the weather so much less predictable than other natural forces? The Torah provides the answer: the behavior of the weather – and rainfall in particular – reflects the behavior of mankind. Hashem determines the weather based on people’s behavior, and adjusts the weather according to what human beings deserve to receive.
In order to better understand the wondrous nature of rainfall, and why it cannot be accurately predicted, let us study the natural processes that create weather patterns.
He Makes Winds His Messengers
King David writes, “Oseh malachav ruhot – He makes winds His messengers” (Tehillim 104:4). Here, too, science has borne out what King David wrote a few thousand years ago. We now know that weather phenomena are fundamentally rooted in the velocity, force, and direction of the global winds, which factor heavily in the fickle nature of weather prediction, because winds are nearly impossible to predict.
How do winds cause weather patterns to emerge?
Of all the planets in our solar system, only the Earth possesses an atmosphere that is capable of sustaining life. Our atmosphere consists of an incredible combination of complex systems that protect life on the planet. Statistically speaking, it is impossible for such a combination to come about by chance. The Earth’s atmosphere, with all of its complex chemical processes, is yet another aspect of the world that attests to the wonders of Hashem’s creation.
Because the Earth is round, different areas on its surface receive different amounts of sunlight, and consequently, the climate tends to vary dramatically from one region to another. The equatorial region enjoys frequent exposure to sunlight because it is directly in the path of the sun’s rays. As a result, it absorbs more heat than it loses, and its climate is particularly warm. In contrast, the North and South Poles only receive indirect exposure to sunlight and lose more heat than they absorb; consequently, the temperature at the poles is extremely low.
This contrast between the equatorial and polar regions is what triggers atmospheric weather patterns. The warm air at the equator rises to the upper levels of the atmosphere, where the drastic difference in temperature between the equator and the poles causes the heat to flow toward the poles via one northerly wind and one southerly wind. As they get closer to the poles, the winds begin to cool off and sink, and the cool air in the lower levels of the atmosphere begins to flow toward the equator in order to create equilibrium. The convergence of the warm winds from the equator and the cold winds emanating from the poles creates whirlwinds when they abruptly alter their course; it also causes storms that eventually lead to rainfall.
Interestingly, King Solomon already tells us: “The northern wind creates rain” (Mishle 25:23). He specifies the northern wind because he is referring to Eretz Yisrael, which is located in the Northern Hemisphere (like most countries in the inhabited world), where the cold northerly wind is the one that causes rain to fall.
Why are winds so unpredictable?
The temperature differential between the equator and the poles is not the only factor that affects the flow of the winds. The constant rotation of the Earth causes the winds blowing toward the poles to move diagonally, in what is known as the Coriolis effect. This is demonstrable: take a globe (or any ball, for that matter), and try to draw a straight line from its center to one of its poles while it rotates. The result will be a diagonal line, not a straight one. Similarly, the winds coming from the equator do not flow directly toward the poles; instead, they move counterclockwise in the Northern Hemisphere, and clockwise in the Southern Hemisphere.
In addition, winds travel at different speeds and routes depending on whether they are flowing across the sea or over land. And there are numerous other phenomena that can affect the winds’ flow, as well. A scientist was once quoted as saying that a butterfly flapping its wings in Australia can generate a hurricane in Florida. Although this is obviously an exaggeration, it reflects a scientific truth – that even a minute environmental change can have great impact on the weather, making accurate weather prediction nearly impossible.
In essence, the atmosphere is an active engine generating the clouds in the sky and the winds that propel them. The vast system is powered by the sun, which heats the water and the air on Earth, thereby causing the global circulation of wind.
The concept of the atmosphere was known to our sages. In the Gemara (Bava Batra 75b), Rav Papa states that the clouds in Jerusalem reach a height of three parsaot – a bit more than seven miles (according to Rav Chaim Naeh’s calculation). Weather conditions appear primarily in the troposphere, the lowest level of the atmosphere, which reaches an altitude of 11 miles at the equator and no more than six miles at the two poles. In Eretz Yisrael, the troposphere extends to an altitude of between seven and nine miles – exactly as Rav Papa indicated.
The Hydraulic Rain Cycle
In the ancient world, the rain cycle was unknown. People did not believe that the rivers and lakes of the world could possibly be filled by rain and snow. For instance, the Nile River does not appear to be linked to precipitation, but we now know that is it filled by rainfall on mountains hundreds of miles away. Until the 17th century, people believed that fresh water in springs, streams, and lakes originated in a vast underground reservoir, or in the ocean, from which it flowed through underground ducts where it somehow became desalinated. The concept of the rain cycle with which we are familiar – wherein water evaporates from the Earth’s surface and forms clouds, which then lead to precipitation –only began to take shape in more recent centuries, after protracted study of the behavior of the world’s water supply.
Nearly 2,000 years ago, however, the Tanna Rabbi Eliezer ben Horkenos already alluded to the existence of this cycle! The Gemara (Taanit 9b) states: “Rabbi Eliezer says that the entire world drinks from the waters of the ocean, as the verse states: ‘And a mist would rise from the ground and water the entire land’ (Beresheet 2:6).” Rabbi Eliezer points out that even though the ocean consists of saltwater, the water that evaporates into the clouds undergoes a process in which the salt remains in the sea, and only the fresh water evaporates. He cites additional proof from the verse, “He gathers the waters of the sea like a wall and places them in treasuries in the deep” (Tehillim 33:7).
The Gemara goes on to provide an exact description of the type of clouds that produce rain. The verse in Zechariah(10:1)states, “Hashem makes hazizim and gives them rain.” Rav Yehuda interprets the word hazizim as referring to a type of cloud called porhot, and Rabbi Yohanan adds that porhot clouds are a sign of rain. The Gemara cites Rav Papa as identifying porhot as an array of thin, wispy clouds beneath heavier clouds. The Anaf Yosef explains that such systems of clouds create thunderstorms that are accompanied by heavy rains. These clouds are rain clouds with powerful electrical charges, which are known to cause thunderstorms.
The presence of these clouds does not guarantee rainfall, however, because, as discussed earlier, Hashem allows rain to fall only if people are worthy. The Gemara relates that the sage Ula was once visiting Bavel and he noticed rain clouds approaching. He advised everyone to move their belongings indoors, but the rain clouds proceeded to bypass the area without releasing any precipitation. Ula commented, “Just as the people of Bavel speak falsehood, so do their rain clouds tell falsehoods.”The Maharsha explains Ula’s comment based on another Gemara that states that people who publicly pledge large sums to charity and then fail to keep their promises cause a drought to strike. The clouds “promise” rain but then fail to deliver on that promise, apropos for people who promise to donate charity but fail to do so.
Moreover, the Gemara comments, sometimes rain will fall, but not where it is needed. If Hashem decrees on Rosh Hashanah that a certain amount of precipitation would be provided that year, but then the people are unworthy of this blessing, He will have the rain fall in a place or at a time where it is not beneficial. Heavy rain clouds occasionally release their water over uninhabited or uncultivated regions, where rain is of little or no benefit. The converse is also true. Sometimes, only a small amount of rainfall is decreed on Rosh Hashanah, because the world is found to be undeserving. But if people later accumulate more merits, Hashem causes that minimal amount of rain to fall in a time and place where it will be most beneficial. The Gemara adds that it is even possible for rain to fall in such a manner that it benefits a single individual or only a very specific area.
Rain as Fertilizer
The Gemara (Ketubot 10b) states that rain fertilizes the land, aiding in the growth of crops. Scientists now know of a process that occurs during rainfall that sheds light on the Gemara’s remark. The atmosphere contains large quantities of nitrogen and oxygen. When these two elements combine, they can provide an immense amount of extremely valuable fertilizer for the soil, but nitrogen generally does not react with oxygen while they are in the air. The force that causes them to react is lightning. A lightning bolt produces a huge amount of heat, which causes a chemical reaction between the nitrogen and oxygen that produces nitric acid, which is then carried to earth by the rain.
The average thunderstorm produces an amount of energy equivalent to the explosion of an eleven kiloton atomic bomb. The air temperature in the vicinity of a lightning bolt can reach up to 27,000 degrees Fahrenheit, and a single lightning bolt can produce 3.75 billion kilowatts, more than the peak production of all the electric plants in the United States. Approximately 100 lightning bolts strike somewhere on Earth every second, and about 10,000 thunderstorms take place every day, thus fertilizing the ground through the nitric acid carried to the earth.
The Most Unpredictable Place on Earth
The Torah teaches that the nature of rainfall in Eretz Yisrael differs from that in other lands:
“For the land that you are coming to inherit it is not like the land of Egypt from which you have emerged, where you would sow your seeds and irrigate [the land] by foot like a vegetable garden. The land that you are going to inherit is a land of mountains and valleys; you will drink water from the rain of the sky. [It is] a land that Hashem, your Gd, constantly inquires about; the eyes of Hashem, your Gd, are upon it from the beginning of the year until the end of year. If you listen to My commandments, which I am commanding you today, to love Hashem your Gd and to serve Him with all your heart and all your soul, then I will provide the rain of your land in its proper time, the rain after the planting and the rain before the harvest, and you shall gather in your grain, your wine, and your oil. And I will provide grass in your fields for your animals, and you shall eat and be satiated.” (Devarim 11:10-15)
The Torah reveals to us here that the rainfall in Eretz Yisrael is subject to a special level of providence. Unlike other parts of the world, which tend to have relatively stable weather patterns, Eretz Yisrael is not characterized by any specific weather patterns. The weather there can undergo extreme changes from one year to the next, fluctuating from one end of the spectrum to the other, and the Torah reveals to us that these changes are a direct result of the Jewish people’s conduct.
We now have fascinating meteorological evidence to explain this phenomenon from a scientific standpoint. Professor Pinchas Alpert, director of the School of Atmospheric Studies at Tel Aviv University, noted recent studies which indicate that Eretz Yisrael occupies a unique geographical position, which leads to its unusual and unique weather conditions. Scientists consider a “healthy” climate to be one where there is a significant amount of sunlight. In general, however, an area with significant exposure to the sun tends to develop a desert-like environment with little precipitation, such as the State of Arizona and the city of Cairo, Egypt. The converse is also true: areas which enjoy significant rainfall tend to have infrequent exposure to the sun, as is the case in large parts of Europe. The area of Jerusalem, however, does not follow the trend. It receives a large amount of sunlight each year (over 3,250 hours per year, on average), and receives the highest average yearly rainfall (500 millimeters) of all the places in the world with a comparable amount of annual sunlight. The converse is also true – Jerusalem receives the most sunlight hours per year out of all the locales that receive a comparable amount of precipitation per year. In all other areas where studies were conducted, meteorologists found that there were either many hours of sunlight and extremely dry weather, or that there were many more millimeters of rainfall, but far fewer yearly hours of sunlight.
Professor Alpert also discovered that Eretz Yisrael occupies a unique position on the globe. Meteorological maps show that it is situated at the point of convergence of four distinct climatic systems: two opposing depressions, and two opposing elevations.
One climatic system, a depression, is located in the northwest and includes the entire continent of Europe, including the United Kingdom, which receive rainfall throughout the year. The second depression is located in the southeast and extends over the Persian Gulf toward India, and it is the primary cause of the monsoon rains in southern Asia.
At the same time, the other two corners of Eretz Yisrael adjoin systems of elevation, which are areas of high pressure that result in dry, rainless climates. One of these systems is located to the northeast, above Asia, and the other is located in the southwest, from North Africa and the Sahara Desert through the center of the Atlantic Ocean, which is a desert-like, dry region.
Eretz Yisrael is located at the exact point where these four weather systems converge, which accounts for the fact that it is subject to often contradictory weather patterns (rainy or dry). These climatic conditions, which exist in an extremely delicate balance, make the country a nightmare for weather forecasters. In practice, it is very difficult to predict, at any given moment, which of these forces will determine the weather conditions . There is not a single other inhabited land in the entire world that experiences such a convergence of weather systems – which is called a “saddle” in scientific terms – with such frequency. The only other point in the world where “saddle points” occur with such frequency is in the middle of an ocean.
This, then, is what the Torah tells us: that Hashem did not choose to settle us in the European countries, whose inhabitants never have to worry about a lack of rain, nor in Egypt, whose water supply comes from the Nile and is essentially guaranteed. It is specifically the Land of Israel, with its wild and extreme changes in weather, which is suited for a nation that is subject to the Creator’s direct providence; in such a land, people realize that their actions can easily change the conditions that affect their very survival.
Written by Rabbi Dovid Kleiner and adapted by The Jewish World of Wonders.