Alarm (Abjuration, Evocation)

Range: 10 yards
Components: V, S, M
Duration: 4 hours + 30 minutes/level
Casting Time: 1 round
Area of Effect: Up to a 20-foot cube
Saving Throw: None

When an alarm spell is cast, the wizard enchants a chosen area to react to the presence of intruding creatures. The initial guideline states the spell triggers for anything ‘larger than a normal rat.’

Recognizing the inherent imprecision of such a measure, the spell description further clarifies this threshold: the alarm is specifically set off by any creature that is either larger than approximately one-half cubic foot in volume OR weighs more than about three pounds. Anything larger than about one-half cubic foot in volume or more than about three pounds in weight.

The wizard can tailor the alarm’s protective ward to specific features within the environment. For instance, it can be shaped to cover a portal, a defined section of floor, or a flight of stairs. The spell’s flexibility also allows it to protect other strategically important, contiguous spaces or discrete objects—such as a treasure chest, a crucial window, or a segment of a narrow passage—provided the entire designated area fits within the maximum confines of a 20-foot cube.

When the Alarm spell is triggered by a qualifying creature, its distinctive audible alert sounds for 1 full round and then automatically ceases. It’s critical to understand two key aspects of this mechanic:

Spell Persistence and Multiple Triggers: The cessation of the sound does not mean the Alarm spell itself has expired. The magical ward remains active for its entire original duration (e.g., 4 hours + 30 minutes/level), ready to detect subsequent intrusions. Each new, separate qualifying trigger will cause the alarm sound to activate again for another full round.
Detecting Multiple Threats: This reset capability allows the spell to signal multiple incursions over time. If different threats enter the warded area in separate rounds, each will initiate its own distinct, one-round alert. This can give the caster an indication of repeated or staggered entries. However, if multiple intruders were to enter the warded area all within the same round, this would likely result in a single, continuous one-round activation of the sound triggered by the first creature, rather than distinct pings for each intruder within that single round.

The Alarm spell is a robust Prime Material ward. It’s bypassed by those truly existing on other planes at the moment of passage, but it’s notably effective at detecting beings who are present on the Prime Material Plane, even if they are attempting to use stealth, flight, invisibility, or more esoteric forms like incorporeality or gaseousness to avoid detection by mundane means.

The wizard can also choose to end the Alarm spell prematurely. By speaking a single designated word, they can immediately dismiss the ward; this does not usually expend an action and can be done at any time, regardless of the initiative order.

Casting the Alarm spell requires two specific material components:

A bell, which, while traditionally depicted as tiny, can be of any practical size suitable to the wizard. This bell is not consumed in the casting process. Crucially, in this revised understanding, this material bell serves as the actual source of the alarm’s sound, which, as discussed previously, can be customized by the caster to be a specific sound or set of sounds beyond a simple ringing.

A “piece of silvered wire” (rather than solid silver wire), meaning a wire of a base metal that has been thoroughly coated by being immersed in silver. This silvered wire is also not normally consumed during the casting. However, it may be uniquely expended if the magical ward itself sustains significant disruption or the wire component itself is directly damaged during the spell’s existence or upon a forceful triggering.

Spell Insights and Observations

Advanced Early Warning & Perimeter Control

Core Function: Its primary role remains unparalleled for a 1st-level spell: securing campsites, dungeon rooms, retreat paths, or chokepoints. The knowledge that it clearly re-triggers for intrusions in separate rounds provides better intelligence on staggered enemy approaches.
Strategic Placement: Ward narrow passages to funnel enemies, protect flanks, or guard essential items/locations. The flexible shaping (within the 20-foot cube limit) is key to covering non-standard areas like specific objects or irregular sections of terrain.

Information via Customizable Sound

Coded Signals: The ability to choose the alarm’s sound (originating from the component bell) is a significant tactical upgrade. A party could agree on specific sounds for alarms set in different locations or by different casters, providing instant, nuanced information at a distance (e.g., a “hawk’s cry” for aerial approach, a “wolf’s howl” for ground intruders to the north).
Psychological Warfare & Deception: Employ sounds designed to intimidate (a monstrous roar), mislead (the sound of a common animal to create complacency), or create diversions (a sudden, unexpected loud noise in a tense situation).
DM-Dependent Subtlety: Could a very soft, distinct sound be chosen for the bell that only alerts the party at close range without broadcasting to distant enemies? This depends on how the DM rules the bell’s sound projection versus the spell’s 60ft magical audibility. If the magic amplifies a characteristic sound from the bell to 60ft, then true subtlety might be hard. If the bell itself dictates volume, then a tiny, quiet bell might offer a stealthier alert.

Synergies and Vulnerabilities

With Obscurement/Illusions: Combine Alarm with Fog Cloud, Darkness, or illusionary walls. Enemies blundering into the obscured area trigger the Alarm, creating confusion and alerting the party to their precise (albeit unseen) location.
Countering Stealth: Its ability to detect invisible creatures remains a primary strength.
Weakness to Silence: The audible nature of this revised alarm (tied to the bell) makes it vulnerable to a well-placed Silence, 15′ Radius spell encompassing the bell or the listeners.
New Vulnerability (The Bell): If the material component bell is now the distinct source of the sound, it introduces a new tactical consideration. Can observant enemies spot the bell if it’s somehow visible or incorporated into the warded area’s appearance? Could they attempt to muffle, steal, or destroy it after casting to neutralize the sound aspect of the Alarm? This adds a new layer for both casters (protecting their bell) and their opponents.