diff --git a/etc/devd.conf b/etc/devd.conf
index cc7a20871a26..f9453ecde2f3 100644
--- a/etc/devd.conf
+++ b/etc/devd.conf
@@ -74,7 +74,17 @@ nomatch 0 {
 notify 10 {
 	match "system"		"ACPI";
 	match "subsystem"	"ACAD";
-	action			"/etc/rc.d/power_profile $notify";
+	action "/etc/rc.d/power_profile $notify";
+};
+
+# Notify all users before beginning emergency shutdown when we get
+# a _CRT or _HOT thermal event and we're going to power down the system
+# very soon.
+notify 10 {
+	match "system"		"ACPI";
+	match "subsystem"	"Thermal";
+	match "notify"		"0xcc";
+	action "logger -p kern.emerg 'WARNING: system temperature too high, shutting down soon!'";
 };
 
 /* EXAMPLES TO END OF FILE
diff --git a/share/man/man4/acpi_thermal.4 b/share/man/man4/acpi_thermal.4
index d22bf690e3b1..28467fa1eff8 100644
--- a/share/man/man4/acpi_thermal.4
+++ b/share/man/man4/acpi_thermal.4
@@ -115,6 +115,9 @@ Current temperature has changed.
 One or more trip points (_ACx, _PSV) have changed.
 .It Li 0x82
 One or more device lists (_ALx, _PSL, _TZD) have changed.
+.It Li 0xcc
+Non-standard notify that the system will shutdown if the temperature
+stays above _CRT or _HOT for one more poll cycle.
 .El
 .El
 .Sh SEE ALSO
diff --git a/sys/dev/acpica/acpi_thermal.c b/sys/dev/acpica/acpi_thermal.c
index 32fb55157c06..03d50cedd117 100644
--- a/sys/dev/acpica/acpi_thermal.c
+++ b/sys/dev/acpica/acpi_thermal.c
@@ -49,9 +49,10 @@ ACPI_MODULE_NAME("THERMAL")
 #define TZ_ZEROC	2732
 #define TZ_KELVTOC(x)	(((x) - TZ_ZEROC) / 10), (((x) - TZ_ZEROC) % 10)
 
-#define TZ_NOTIFY_TEMPERATURE	0x80
-#define TZ_NOTIFY_LEVELS	0x81
-#define TZ_NOTIFY_DEVICES	0x82
+#define TZ_NOTIFY_TEMPERATURE	0x80 /* Temperature changed. */
+#define TZ_NOTIFY_LEVELS	0x81 /* Cooling levels changed. */
+#define TZ_NOTIFY_DEVICES	0x82 /* Device lists changed. */
+#define TZ_NOTIFY_CRITICAL	0xcc /* Fake notify that _CRT/_HOT reached. */
 
 /* Check for temperature changes every 10 seconds by default */
 #define TZ_POLLRATE	10
@@ -59,6 +60,9 @@ ACPI_MODULE_NAME("THERMAL")
 /* Make sure the reported temperature is valid for this number of polls. */
 #define TZ_VALIDCHECKS	3
 
+/* Notify the user we will be shutting down in one more poll cycle. */
+#define TZ_NOTIFYCOUNT	(TZ_VALIDCHECKS - 1)
+
 /* ACPI spec defines this */
 #define TZ_NUMLEVELS	10
 struct acpi_tz_zone {
@@ -481,14 +485,18 @@ acpi_tz_monitor(void *Context)
      * for one poll cycle.  It is suspected this is due to the embedded
      * controller timing out.  A typical value is 138C for one cycle on
      * a system that is otherwise 65C.
+     *
+     * If we're almost at that threshold, notify the user through devd(8).
      */
     if ((newflags & (TZ_THFLAG_HOT | TZ_THFLAG_CRT)) != 0) {
-	if (++sc->tz_validchecks == TZ_VALIDCHECKS) {
+	sc->tz_validchecks++;
+	if (sc->tz_validchecks == TZ_VALIDCHECKS) {
 	    device_printf(sc->tz_dev,
 		"WARNING - current temperature (%d.%dC) exceeds safe limits\n",
 		TZ_KELVTOC(sc->tz_temperature));
 	    shutdown_nice(RB_POWEROFF);
-	}
+	} else if (sc->tz_validchecks == TZ_NOTIFYCOUNT)
+	    acpi_UserNotify("Thermal", sc->tz_handle, TZ_NOTIFY_CRITICAL);
     } else {
 	sc->tz_validchecks = 0;
     }