Malachor V: a Force wound.
An extremely destructive disturbance in the Force is referred to as a wound in the Force, also called an echo or a hole in the Force. It represents a flaw in the very essence of the Force, typically resulting from some deeply scarring occurrence. Since the Force is intertwined with all living beings, the mass eradication of life, especially when concentrated within a short timeframe, gives rise to these wounds.
The genesis of Force wounds is always linked to events involving widespread death. Given that all life throughout the galaxy is connected, the sudden loss of many lives causes a kind of localized trauma to the Force, similar to the sensation of a sentient being losing a limb. These wounds transform the area at their center into a place of darkness, saturated with the lingering agony, fear, and suffering of those who perished. Force wounds are often found in locations where traumatic events have unfolded, like Malachor V and Alderaan. However, they can also manifest within individuals, as seen with Meetra Surik and Darth Nihilus.
In certain instances, when a strong connection exists between two Force-sensitive individuals (such as twins like Luke Skywalker and Leia Organa Solo, or the master-apprentice bond between Satele Shan and Kao Cen Darach), the death of one can be felt by the other across vast interstellar distances.
Similar to ripples spreading across water, wounds in the Force send out echoes through space. These echoes course through the Force, sounding like a scream that is only audible to Force-adepts. In the wake of significant tragedies, such as the destruction of Alderaan or the Battle of Malachor V, a Jedi can sense the reverberations of the event from halfway across the galaxy. These echoes create distortions within the Force, akin to static noise. The interference caused by these wounds makes it difficult to sense any Force-user in close proximity.
Some historians have proposed that the life-destroying influence of the dark side can cause a breach in the Force, particularly when wielded by a powerful figure like a Sith Lord. While this theory isn't universally accepted, it helps explain how figures like Darth Sidious managed to conceal their dark side alignment from the Jedi High Council for so long. It also provides a reason for why the tombs and dwellings of the Sith, such as those on Dxun, Onderon, Korriban, and Yavin 4, remained tainted and corrupted for thousands of years after their abandonment.
A wound in the Force emerged on Malachor V in 3960 BBY during the climactic battle of the Mandalorian Wars. This was triggered when the Jedi General Meetra Surik activated a superweapon known as the Mass Shadow Generator. Surik had a natural talent for forming strong Force bonds with those around her. This ability, though largely subconscious, allowed her to exert influence over her companions and made her a capable leader. However, during the battle of Malachor V, this gift turned into a burden. When she instructed Bao-Dur to activate the Mass Shadow Generator, thousands of soldiers whom Surik had befriended and led into battle were instantly killed. Overwhelmed by the psychic repercussions of the destructive energies she had unleashed, she instinctively severed her connection to the Force to survive. This left her unable to sense the Force, but she continued to radiate the echoes of the suffering she had witnessed.
During the Jedi Civil War, approximately from 3959 to 3956 BBY, Darth Revan strategically utilized locations believed to be at the heart of major Force wounds. These included the Trayus Academy on Malachor V, Freedon Nadd's tomb on Dxun, the Sith Academy on Korriban, and the Rakatan Temple of the Ancients on Lehon. Each of these sites served as clandestine Sith bases. Throughout the conflict, captured Jedi were brought to these locations, where the voracious and corrupting effects of the Force breaches weakened their resolve, making them susceptible to Revan's influence and conversion to the dark side. In these places, he transformed numerous Jedi into loyal Dark Jedi and Sith assassins for his Sith Empire.

In the aftermath of the Jedi Civil War, during the Dark Wars spanning from approximately 3956 to 3951 BBY, the surviving Sith began to delve deeply into ancient Sith practices. These techniques had been rediscovered by Darth Revan, who had observed the devastating effects of the Mandalorian Wars and their impact on the Revanchist Jedi who participated in them.
The leaders of the remaining Sith forces, known as the Sith Triumvirate—Darth Traya, Darth Sion, and Darth Nihilus—mastered the creation and manipulation of Force wounds. This allowed them to conceal their presence, leech power from the destruction of living beings, and hunt down the remaining Jedi through the Force. They and their legions of Sith assassins grew in power with each kill, necessitating a constant cycle of death and consumption to maintain their strength.
When the Jedi Council confronted Surik, years after her exile for joining the Mandalorian Wars, Master Vrook Lamar revealed to her the nature of her being.
The Jedi Masters recognized that if Surik were to succumb to the dark side, she could become a predator of life, much like Darth Nihilus. He was a Sith Lord who had abandoned his humanity in his relentless pursuit of power and to satisfy his insatiable hunger.
Surik eventually returned to Malachor V to face Darth Traya and to attempt to seal the wound that lingered there. Bao-Dur's remote, sent by its maker, was also present on the planet to reactivate the downed Republic ships and provide power to the Mass Shadow Generator. After defeating Traya, Surik ordered the Generator's activation, resulting in the planet's destruction and, ultimately, the sealing of the wound.

More than a century prior to the Battle of Yavin, the Sith Master of Darth Tenebrous became known among later Sith Lords for creating a hole in the Force. This act made the Jedi consciously aware of the dark side for the first time in eight centuries.
Following the rise of Palpatine, Yoda sought refuge on the planet Dagobah, concealing himself within the shadow of a Dark Side Cave. He chose this Force nexus as his sanctuary because it offered a degree of protection from those who sought to find him.
In 0 ABY, Moff Tarkin created a wound in the Force when he used the first Death Star to destroy the planet Alderaan. This event resulted in the instantaneous death of every living organism on the planet. The catastrophic event sent shockwaves through the Force that Obi-Wan Kenobi detected, despite being located in the Outer Rim Territories, far from Alderaan. Even Nova Stihl, an untrained Human male with a high Midi-chlorian count, was affected by the wound in the Force. At the moment of Alderaan's destruction, he was taking a sonic shower to relax. The feeling of so many deaths nearby was enough to cause him to pass out for an extended period of time. He awoke later with the sonic shower still working over him and a nose bleed.
In 11 ABY, Kyp Durron obliterated the Carida system using the Sun Crusher, and the resulting disturbance was felt by students at the Jedi Praxeum on Yavin 4. The massacre of the Eol Sha colonists on Dantooine also generated echoes that were sensed by the Jedi trainee Gantoris. Another disturbance detected by the students on Yavin 4 was the slaughter on Pydyr committed by Kueller in 17 ABY.
Leia Organa Solo also experienced the deaths of her father and Darth Sidious in orbit around Endor, where the Death Star was destroyed during the Battle of Endor, while waiting for the Noghri delegation. The dark side's power in that location was so intense that she fainted for several minutes.
Luke Skywalker sensed the destruction of Sernpidal through the Force.
During the Mission to Myrkr, Anakin Solo was killed, and his death created ripples in the Force. His mother, Leia Organa Solo, and many other Jedi felt this event.
Ben Skywalker, who was born during the Yuuzhan Vong's invasion of the galaxy, possessed such a heightened sensitivity to pain and suffering that he severed his connection to the Force and refrained from using it for much of his early life.
Teneniel Djo felt the deaths of the Hapan Royal Navy crews during the Battle of Fondor, which led to her miscarriage.
In 44 ABY, Abeloth's Destruction of Tahv resulted in a surge of pain that was felt by members of the Lost Tribe of Sith.